I liked it because it had something the other two films lacked: GOOD action. Don't get me wrong, the Nightcrawler intro and the Wolverine/Deathstrike fight scenes were good, but the action overall with both the first two were rather tame. Boring at some points, even.
Everyone says there should be more characterization, which is usually true, but the main characters had characterization up the ying yang the past two movies (all except poor Cyke who pretty much was written out of the last two movies despite having potential in the first), so doing more of the same stuff would've made the movie "blah" in my opinion.
The studio wanted to throw everything in because it was their last movie. And despite the grand opening X3 received, they're not ready to move on a forth film yet (
http://www.superherohype.com/news/x-mennews.php?id=4310 ). As a fan, I'm glad they did get as much in as possible if the franchise doesn't continue.