Generally well done, X-Men: Days of Future Past starts out slow and builds to a strong and satisfying finish.
The film does slightly disappoint in two areas:
First: I'm certainly not a fan of relentless action, but DoFP drags its feet a little too much for modern sensibilities - like that friend you really enjoy hanging out with but you just wish they would walk a little faster.
Second: "The Future" lacks the punch I was hoping for, both esthetically and dramatically. Dark, gritty, war-torn future... good. Last few surviving mutants flying around in their shiny plane and wearing brand new combat suits? Ehhh you're losing my suspension of disbelief. In addition the Sentinel robots of the future are ridiculously overpowered to the point of being neither entertaining nor dramatic.
Still, most of the movie happens in The Past where it sets up some legitimately interesting dynamics between the characters and delivers choice moments of dramatic personal interaction. And then the finale is incredibly moving.
Overall another solid X-Men title that's entirely worth seeing. Stay for the extra scene after the credits!