Back when they first introduced Soranik Natu, I was one of the crowd of people begging them not to make her into Kyle's girlfriend. It was right around the time Jade got killed and The Curse was in full height.
Now that they've actually done it, though, I'm finding myself pretty happy with the couple. This took a bit. I was adamantly opposed to this as of the end of Recharge, she was already a hundred times more fun than anyone they'd set Kyle up with and I worried I'd be upset about them killing this one. After the Star Sapphire storyline I was more open to it, but still cautious because we all know what happens to anyone who gets near Kyle's bed. It grew a bit on me when the two approached each other in the aftermath, mainly because Soranik said she'd never been open to love and it looked like it would be a decent story for her. Most female characters are really developed on the side of love and family, and so get neglected with storylines that aren't about relationships. Soranik up until then had been a career-centric character, we'd never seen a boyfriend or a family member. She was established as a hero to be reckoned with already, so this was genuine character growth on her part. Plus, I wasn't expecting it to last.
Now that they've revealed Sinestro is her father, I'm completely in love with this idea. I really do believe it makes her less likely to be casually killed off. Sure, being Alan's daughter didn't save Jade but on this end the father is already so filled with fear and angst and misery that he's a bad guy on a massive cosmic scale. They don't really need to give Sinestro anything else to be freaked out about, Johns is setting him up quite well with the tragic past. Soranik's death would be an even more unnecessary character death than usual on that point.
Of course, Kyle already has enough death and misery in his past and that's never stopped anyone from offing a relative for him.
Still, I think her place in the relationship arc between Kyle and Sinestro is a potentially safe one. She hates her father, but from the position of a person who cherishes life in all forms. As it is Kyle now has a very tense reason to keep Sinestro alive (beyond his usual moral objections), and Sinestro has yet another reason to hate and target Kyle, but new consequences for it. If Soranik were to die and they were to blame each other, that dynamic would be fundamentally less interesting and both characters would lose a dimension of angst.
Beyond being comfortable with Soranik's chances of survival, I have to say she is the first girlfriend of Kyle's that I've actually liked. Part of that is how she was established before she got involved with him. Donna and Jade were both well-established heroes from teambooks before Kyle was even created, but neither were properly rooted anywhere.
Donna had been bounced around from Teen Titans to various identities and power sets and even personality changes when she was pulled into Green Lantern and depowered. She fulfilled a joint girlfriend/mentor role where she was wise, experienced in heroics, and more emotionally mature than Kyle, but she was still insecure and jealous of other women. She also didn't properly belong in Green Lantern so she walked out on him in as soon as someone wanted to pull her. (The "lost all memory of why she loved him" explanation was brilliant, though. I wish he'd whine about that more.) She's considerably more likable as the Ex-Girlfriend who is still friendly but will never likely be involved with him again.
Jade was arguably a Green Lantern character, but not Kyle's sort of Green Lantern. She was one of those Infinity Inc characters that DC didn't know what to do with, so she never really got a proper fit outside of Green Lantern. I don't think she got a proper fit insider of Green Lantern. It always came off as a rather clumsy attempt to mash the Golden Age mystic legacy with the current space-opera version. Don't get me wrong, I like the explanation that the Starheart is the same sort of energy (it may even be a Parallax-style entity), and it comes from outer space so Jenny and Alan are connected, and friendly, but not really a part of the GLC. But the relationship between Kyle and Jade just seemed like an arranged marriage to join the earthbound and spacefaring Green Lantern families together. Every time they got together, I cringed. It seemed inorganic. As a result, I suspect I hated Jade more than she deserved. She just didn't fit the parts of the franchise that appealed to me. She ended up filling the same role as Donna, only a little less competent, a lot less openly jealous and a lot more insecure.
Careerwise, both women were said to be photographers but never seen holding a camera. Both women were professional heroes, but both were depowered. The one that was repowered during the relationship (Jade), was normally shown to be simply not as a good a hero as Kyle was. Not a bad hero, just not as good as Kyle. And since she had the same power set and more experience, one could only conclude that she was either inherently inferior or just wasn't putting in the necessary effort. (I suspect its the latter.) Ultimately, the career didn't matter because their primary role in the book was "love interest" from the moment of introduction, and their primary occupation was "girlfriend/nursemaid."
Soranik is different. She is pretty firmly established as a space-faring Green Lantern character. If Green Lantern Corps were to end next month, it is possible that she would surface as a member of the Global Guardians or a contestant on a reality TV show, but as of the start of this relationship she doesn't have a history of being traded from office to office as writers try to figure out what to do with her. (Neither does Kyle, even though he switches books a lot. He's still in the same franchise.) She's in the franchise that she belongs in, and no other editor or writer will have a claim.
In-story-wise, she fits Kyle's world better than the other two. People argue that in Marz's run Kyle was an earthbound character, but I read that run too. He spends the second storyline lost in space. Every other storyline, he goes to outer space. He spends one-shots in space. In Morrison's JLA, where he most shined as a character, he was on a team based on the moon and a large number of the threats he was called in for were space-based. He has always been a space Green Lantern, even when he was living in New York. He's where he's best suited to be right now, in outer space turning the beauty and weirdness of the universe into something relatable. Yes, Kyle has a very down-to-earth temperament, but that's part of why he and Guy suit the wider universe best. They bring Earth to Oa for us, and their interactions and insights during adventures highlight the humanity in all of these strange alien characters.
Jade was never a good fit for outer space (this may have something to do with her mother being a plant-based villainess), and one of the few good things Winick did was have her realize that and go home. One of the really unsettling things about Jade's death was that it happened in outer space rather than on Earth. That just wasn't her arena, and the fact that she died out there just underscored it. Come to think of it, that may be why I so despise Jade as the primary female Lantern in the DCU. Because she's ultimately an earthly character, and the things I love about Green Lantern aren't even in orbit. She inadvertently sends the message that girls don't really belong there because the only female character obviously doesn't belong in outer space. Katma Tui, Arisia, Brik, Boodika, Soranik Natu, Iolande, even Carol Ferris (she has the same hook Hal does, an Earth pilot who gets hired by aliens) are all preferable because they suit the setting better. I wish I could explain just what it was, maybe its just that all of Jade's legacy ties are earthbound Infinity Inc and JSA matters, or maybe it was that no writer ever took her out to space on her own (she only ever seemed to go when Kyle went), or that she just didn't do well against space-based baddies, but Jade just didn't work in space.
Donna does considerably better in outer space, but she's still a freaking Amazon. I don't care how many times they send the Titans to outer space, or how desperately they tie the Olympians to the Source. It's like Wonder Woman in outer space. It's pretty cool if you write it right, and she can handle it, but ultimately she's just visiting. She's not at home there either.
Soranik is a space alien and a space-faring Green Lantern, and the daughter of a well-established space-alien villain. In temperament she bears a striking resemblance to Bones McCoy. She definitely suits outer space.
Careerwise, Soranik is already established as a Doctor first and everything else second. In speculative fiction, medicine seems to be a safe female niche but that doesn't erase the respectability and importance of Natu's position. She's instantly valuable in every adventure for her professional skill set. She will never be relegated to the background position of "supportive girlfriend" simply because she's dating Kyle. Her job is too damned useful. If she's there and just standing around while he takes charge of the situation, a male character who was not dating Kyle would be there and simply standing around waiting for someone to get hurt so he could be useful. If she breaks up with Kyle so that he can go to his old girlfriend, she'll still be useful to the team because she can do things like deliver a baby in the middle of a battlefield. If in the brainstorming session a writer suggests killing off Soranik, someone can argue that they don't want to kill off the character with all the healing skill and then have to introduce another doctor. (I haven't the slightest idea what happens in brainstorming sessions, but you have to admit that argument couldn't be used to save Jade or Katma.) Hell, if it does get public that they're dating, and Kyle selects Soranik for an important mission there's a very obvious reason for it besides they're sleeping together -- because he wants someone around who can jumpstart his heart more than just figuratively. Just in case, y'know. She's never going to just be the girlfriend, and that's because of something that was set up from her very first appearance over two years before she started dating Kyle Rayner. Something that makes her character unique among Green Lanterns, and valuable beyond just her emotional impact.
Personality-wise, she's a pleasant break from the pattern. Jade and Donna both seemed to have same sunny, friendly attitude. Jade got passive-aggressive and Donna would start snapping at people when under stress. They fought when actually threatened, but tended to be conciliatory otherwise. They would only pull out the arrogance when someone was being a jackass and needed to be put in their place. They were sweet girls with highly developed social skills. They were both more emotionally mature than Kyle, and mentored him in both heroism and love.
Soranik has a short fuse and a surgeon's ego. She's insecure about a lot of things but hides it behind a very harsh demeanor. Her default attitude is arrogance, even though she fights less with the other Lanterns (Guy, Isamot, Iolande) now she still carries a cold arrogance when dealing with them. She softens when treating patients or talking to Kyle. She's confrontational even when there's no threat of violence. She's not a friendly person by nature, and social skill isn't really a priority for her. She's never sweet, even with Kyle. She's never, ever passive about anything.
In emotional maturity, I'd put her maybe at the same level as Kyle, probably a bit behind the curve in some aspects, but a bit ahead of him in others. She strikes me as physically older, and definitely more scholarly which offsets his greater experience in love and heroism. She helps him with a major emotional problem right after they get together, but the way she approaches the problem (his drawings of dead lanterns) is unusual. She's caring but keeps a clinical distance the other women wouldn't have been able to pull off. Jade and Donna's heart to hearts with Kyle always struck me as having a strange half-patronizing/half-pleading tone to them, where the girlfriend would protest that she cares for and loves Kyle but to listen to her because she knows better. Soranik doesn't plead that she loves Kyle, she tells him she cares about him as a way of shifting the debate away from her position as a medical expert who can just dole out orders to that of a friend who wants to understand him but might not necessarily know better. She actually acknowledges that the drawings themselves are a positive step in working through his traumas, which is something I can't see his previous girlfriends having done. (I've no doubt I'll be corrected if I'm wrong in this area.) In the end she offers a solution as a suggestion rather than a prescription, which is a pretty impressive feat for a Doctor.
Kyle's got a very friendly, approachable attitude. As Green Lanterns go he's pretty short on arrogance. He can be sweet, and passive aggressive. He was very much like his last two girlfriends, except he wasn't as mature as they were. Soranik has a completely different personality. She and Kyle share a common set of values, so the differences complement each other rather than clash.
Some of those common values come from just fitting the same part of the DCU. From the first time Kyle fought Parallax, he was tied to the betterment universe above all other things, above self, above family, above even his own species. Jade was always a personal-level hero, who would show up and do her duty during the giant crossover but ultimately be focused on her own loved ones. That's not bad, it's just earthly. Soranik Natu has the same calling Kyle does, for the universe above your own comfort, your own ambitions, your own planet. After the universe itself, Soranik and Kyle share a dedication to the sanctity of life, to the Green Lantern Corps (the people, not the rules or the bosses of the Green Lantern Corps), and to stopping the spread of fear across the universe.
Even before that awesome scene in Green Lantern Corps #41 (though it was nice to see dating Kyle didn't make her suddenly suck), she was considerably better than any girl Rayner's ever dated. Her career cushions her from falling into the "just a girlfriend" trap, her personality makes the relationship more interesting than the previous ones, and her connection to the franchise's major bad guy adds a layer of protection against being casually tossed into a refrigerator. So I have to say I'm pretty happy with what I've seen so far, despite worrying a bit about Kyle's Curse.