It just felt right. I didn't like the first one that much, it felt like an introduction that it actually was. X2 was great in a similar way as this one - the action is more intense, and the superpowers really are superpowers (almost too much in the third, actually, but they rule on big screen - if I saw this one from a small tv for the first time, I might not be that impressed).
Character development - well, there's not much of it really... Storm gets more room this time, but the scenes are centered at the usual suspects. Wolverine still pretty much leads the action. A good thing is that some key characters are played out unexpectedly so that the others get a little more screen time.
I'm almost a total stranger to X comics, so I can't comment on that, but these movies are my favorites in the superhero genre.
One additional thing: When the movie was starting, I realized I had managed to not see a single trailer or other advertizing beforehand, without even trying; I think the movie's effect on me got a boost from that fact. This is something I want to exercise more. Trailers just suck nowadays, giving all the one-liners and biggest kabooms out too soon while still being predictable and boring (please, don't always hire that same deep-voiced dork for saying 'This Summer, an adventure begins' and other equally stupid crap). The same thing happened to me with the first Matrix, I knew nothing about it beforehand - and boy, did it hit me in the head back then...
