I saw X-Men:Days of Future Past last weekend and I thought it was really well done. As far as how I would rank it among the other X-Men franchise movies - I would definitely put it near the top and the fact that it did it's best to right the X-Men Movie Franchise "ship" earns it a lot of kudos in my book.
It was great seeing Fassbender as Magneto again - he was the best part of X-Men: First Class and continued to shine here. It was also nice to see Patrick Stewart back as Professor X, doing more than just a post-credits scene or a bad CGI cameo (I'm still not convinced he even showed up to shoot that scene - I think they simply used what they had on hand from the young Jean Gray scene in X-Men: The Last Stand - the quality of that scene in X-Men Origins: Wolverine was so bad, I think anything is possible really)
Quicksilver was well done and a great way to have a sequence where mutant powers can be showcased to provide levity and comic relief in a story that was at points very grim and macabre. I would have never thought we'd see Sentinels rip Colossus in half, decapitate Iceman or impale Storm - but we did.
I'm looking forward to X-Men: Apocalypse in 2016, I hope they can keep the momentum going and keep getting better.
Do I wish the rights were with Disney so X-Men could cross pollinate with Avengers? Of course. Same thing goes with Spider-man - but those studios seem to have no intention in letting go of their franchises anytime soon.
Are there still glaring discrepancies across the movies in the franchise? Sure the universe seems to have two Emma Frosts, Havok is 30+ years older than Cyclops, there are two very different Trasks, multiple variations of Stryker, etc...
But if they are finally recognizing that having these discrepancies was really hurting their ability to tell coherent stories, then I'm glad they seem to finally be interested in building a more coherent set of connected movies.