I'll call it a slightly-above-average end to a slightly-above-average series, a movie that I think will probably not age all that well or be much thought about a few years from now, one that fails to reach the bar set by X2, much less Spider-man 2, which for my money has become the gold standard for superhero movies.
Pros: Lots of interesting heroes and villians portrayed in a pretty short span of time. The characterization for the minor characters was generally pretty good--brief, fairly one-dimensional, but nonetheless effective given the time/space limitations. Much of the action's pretty good. I've never liked Beast, really, but I thought Grammer did a pretty good job with him. Ian McKellen was, of course, superlative, and he carries much of this picture on his powerful shoulders. Wolverine's never been my favorite character, but it's nice to actually see him be a little more of the stalker, even for just a minute (and not all that effectively).
Cons: Quite a few, unfortunately.
-- The length. Longer doesn't always mean better, but at about 1:40, this movie can't possibly cover all the territory it sets out to. Of course we were never going to get the whole Phoenix/Dark Pheonix saga, and for the most part I don't mind the character revision, but what we get here was a squished-together Phoenix mini-saga plus the end of the main Magneto storyline. Either would've been enough for a film; together, they feel like mashed potatoes. I'm sure the 14-month development schedule can be blamed for some of this, as can the absence of Singer. (As an aside, why can't this series have a single naming convention--X-Men, X2, X-Men 3? Odd.)
-- Phoenix. This builds off of the first con. I've always liked Famke as Jean, and I thought she did a pretty good job in X2, but here, after the opening scene and her time at her home again, she's got nothing to do but stand around and glare. Sure, she gets kinda scary, but she's hardly the emotional weight for this story, which leads to ...
-- Xavier. What he gets to do in this movie, he does pretty well, although his I-don't-have-to-explain-myself-to-you-least-of-all bit is tiresome and wearily delivered. I don't know whether Stewart wanted out, but he seems at the exhaustion point here, and it's probably just as well that his role is minor.
-- Halle. Not a Halle-hater here, but if not as an actress at least as Storm she's got severe limitations. If you're the filmmaker and counting on her to carry the emotional weight of your movie, you're in trouble. She pretty much utterly fails to deliver; her speech at the school is utterly unconvincing, and her appeal to Wolverine to "be with them" is, well, I guess unsuccessful even for him, 'cause he goes and runs off. (I know he comes back, but ...)
-- Insufficient impact. Not surprisingly, I didn't find much emotional resonance here. What should've been a big moment at the end just feels flat to me.
This movie isn't the disaster that one might fairly have predicted from all the off-the-screen hijinks and the rushed development schedule. I can't help feeling like those of us who liked the series and the books deserved better.
