Just got back and I really enjoyed it. Like others have said, it's great but in a different way. Avengers 1 is the first love, just like the first installment of many major movies, you give that edge to the first time. That being said, it's probably an 8 or 8.5 with Avengers 1 barely edging it out by a .5.
What I liked...
Loved all the time spent on each character. Regardless who you wanted to see most, I think you got your money's worth.
Ultron was brilliant in a lot of ways. If you're going for this piece of Tony, piece of whatever else, there's so many nuances that kept you in touch with that part of the story.
Fight scenes were excellent and I was never bored between each fight. Just to touch on a couple of things on the forums, I never felt IM had Hulk even remotely under control but was constantly working just to keep the suit together and Hulk distracted. I felt he was simply trying to survive the entire fight and each time he had an upperhand, he quickly was torn apart until he finally just dropped him into a building. End battle was awesome, I mean really, really awesome.
Also, I really didn't feel like the rehashing the old villain plot was a big issue. First off, every villain from 1950's radio shows all the way to today essentially work the same way. Secondly, I think it is more the personalities they have established that are the problems more so than any villain exploiting them. Ultimately, I think it sets up the Civil War nicely and Thanos.
Couple of things I was expecting but didn't happen.
I was hoping Cap would have moved the hammer a bit more or even picked it up.
When Hulk was flying away, the ending music from the old TV show would have been an awesome touch
On a more serious note, I did feel like things were a little choppy and that's probably my biggest complaint. Every now and then I would feel a small disconnect and then it would settle.
Overall... great movie, a must see and I think however they decide to handle the Infinity Wars will either make this installment better or worse.
