As is the problem with the X-movies, the cast is sometimes too big to focus on them all adequetely. I liked Jean, Scott and Kurt. The Horsemen aside from Magneto were pretty much non-characters, IMO.
Fassbender and McEvoy as Magneto and Professor X were fantastic as usual - they could pretty much carry the film by themselves. Evan Peters as Quicksilver (with a bigger role this time round) was a treat.
Disagree with the critics on this one. I think it may be the best of the new trilogy to date, though I've enjoyed them all quite a lot.