Watched it, and being a fan of the first two movies, I loved it. I hope I'm not clouded by bias, but it was extremely entertaining and I was moved by the deterioration of Xavier's and Mystique's friendship, along with the friendship between Xavier and Magneto. I liked the interaction between all the X-Men really, shame everything has to go to hell so fast.
The nods and references to past movies (or is it future movies? O.O) was cool. And though some critics found Jennifer Lawrence not as compelling as Mystique, she appealed to me simply by showing that Mystique was an actual human being once before becoming a mostly silent, but extremely sexy henchwoman.
A major flaw though was the underdevelopment of the supporting characters, though I guess this is inevitable considering the series's track record. I get Angel feeling pissed that she is labelled a freak, but how does she get from relatively sympathetic stripper to finding her place with the X-Men and chilling out right to joining Shaw with a smirk on her face all in the space of one night? So yeah underdeveloped supporting characters (was Havok even necessary?) and one-dimensional villain sidekicks once again plague an X-Men movie, though I hope this will be fixed since they plan this to the first of a new trilogy.