I enjoyed it. Still coming to terms with having to relax on the continuity. i.e. why can Xavier still walk and use his powers when he and Magneto first visit Jean? I knew going into it I'd have to be forgiving but there's just so many errors! In any case, any scene with Blink in it was my favorite. Obviously, someone was a Portal fan. 
Thankful it wasn't "The Wolverine Show".
Minor spoilers:
Fridge logic: in the original history where they didn't prevent the (no spoiler) critical event, eventually Xavier hits rock bottom and decides to climb out of his drug-addled seclusion and reconcile with Erik, at least temporarily, to try to restart their original mission to seek out and help mutants. At that moment in time (late 80s perhaps) Xavier is only using the drug as Beast recommended: enough to allow him to walk, but (very minor spoiler) not enough to completely shut his powers down. Eventually though, like most drugs, Xavier builds up a partial immunity to it and has to take so much to restore his ability to walk it also affects his powers too much, and he decides to forgo the drug. Thus, in the 70s he is what we see in DoFP, in the 80s he is what we see in Last Stand, and in the 90s he's become what we see in X-Men.
As Magneto says near the end of the movie (paraphrased) "so much wasted time."
Addressing a different question, how did Xavier come back at all in the Wolverine stinger and Days of Future Past? Upon reflection, it makes sense: at the end of Last Stand its suggested that Xavier somehow transferred his consciousness to the coma patient being treated by Moira. Question: why was Moira treating a basically brain dead person? Maybe because while he had serious neurological problems, he also had the x-gene for telepathy: his brain had no consciousness but he was never observed to have zero brain function because he was still able to react telepathically to other people. And that's how Xavier was able to transfer to him specifically: not only would Xavier not be destroying another person's consciousness by taking the body over, it was a body he could get to because it was itself a strong telepath he could reach. Why is Xavier still paralyzed at the end of The Wolverine? Because he had not long ago possessed someone that had been bed ridden all his life and had various neurological problems. The body itself probably had little ability to use its limbs and it probably took a lot of effort and practice just to be able to use its arms. Walking was out of the question. Why does he look like his old self? He looks like Xavier because Xavier was *projecting* his original appearance to Wolverine so he would recognize him at the airport.
But why does he also look like himself in Days? Think about how the X-Men were fighting in the future, and how perfectly they were coordinating their fight.
Xavier had them mind-linked. So to all of them, he also looked like his original self because he was projecting that image to their minds automatically. He still can't walk because physical therapy sessions to build up his legs and neurological ability to walk was probably not a priority by that point.
