Saw it. Loved it. Hard to discuss without spoilers but I'll just say that the way they blended the two casts, old and new, was extremely well done. I was also a bit surprised at how "adult" this X-Men film was. There was more profanity than you'd typically get from a comic book film, a slew of mortal violence, and even one nude scene. lol I thought it was all appropriately done and fit well for the movie, I didn't mind it one bit, but it just surprised me. The themes of the plot are also quite mature and may be difficult (or boring) for some kids so be warned if you're planning to take yours.
For the story, ending, and after-credits scene I have a lot of questions and discussion points but I'll wait to see if anyone else is on board before I start dropping spoilers.