Just saw this movie today and I enjoyed it overall. I'm glad Singer is back at the helm of the X films, story wise, I enjoyed X1 and X2, and I see DoTFP as a perfect continuation and reboot of the franchise. Only thing that disappointed me was the action scenes, what we saw in the trailer was pretty much all we got, Singer has never been really great with action.
Just some of my thoughts, spoilers ahead, so be warned.
I really liked Quicksilver, they did a great job with his character, really changed my opinion when I first saw the preview images of him. I'm glad it wasn't another Wolvie movie, he was there and pivotal to the plot, but he didn't steal the spotlight. Fassbender and McAvoy did a really awesome job in this movie, I loved their interactions and I was hoping they would team up together against the Sentinels with a team of X-Men instead of Magneto going postal. Mystique could have killed Trask so easily in so many ways, she could have just disguise as his secretary, wait till he comes to work one day and BAM!, but I guess hunting him down was needed to move the story forward. Watching the future Sentinels kill off the X-Men was sweet, lol, knowing that they would all come back once the past is changed anyway. I was hoping for a big showdown with Magneto and an actual team of X-Men at the White House at the end. They could have bought Havok and Quicksilver back in with Beast and Wolverine against Magneto and the Sentinels.
The events of X1-X3 may have happened differently or never happen at all since the past has been altered. Mystique may have never joined the Brotherhood after what happened at the end of DoTFP, it would explain Scott and Jean being alive at the end, Rouge staying as an X-Man, and Jean not going Phoenix and killing Scott and Xavier. I hope Singer brings Cyclops back in AoA and do his character justice. The X-Men films continuity has been all over the place, hope with this "reset", they do it right this time.