I saw it yesterday and I really liked it but it has some flaws which hurt the movie.
I'll start with the negatives on the Movie:
The major problem in this movie is the fast pacing and overbloated subplots which could haven been done well, if some of the action scenes would have been cut or reduced because there tons of it with barely any time to breath.
Thus some characters like Quicksilver & Scarlet Witch or the relationship between Black Widow and Banner hadn't got any development, it was just thrown in the movie. The creation of Ultron was tbh disappointing, I mean Stark and Banner are working on this project for 3 days or so, which failed every time but after they leave, it automatically succeeded and Ultron turned or rather born evil.
The fast pacing is also due to the quick editing, especially in the fights scenes which also made it worse in 3D, so you couldn't really what was going on in some scenes.
Quicksilvers death was... I dunno hasty, he shouldn't have died. I know that the movies lack the sense of danger where a character can die, but letting a character die in just one movie where he got his debut? That's a bit quick for my taste. Some of the action scenes (flying, jumping) and CGI were bad though (like in the trailer where they are all on the screen jumping), but not all of it though.
Last but not least, of course the villain was weak like in every MCU movie, he didn't really got to fight much but the mindless robots did.
The Positives:
Well there is not much to say, the chemistry between the actors/characters were great and they did feel like a team, unlike in Avengers 1 where they (all) just teamed up towards the end of the movie. The new characters Scarlet Witch, Quicksilver, Ultron and Vision were great and interesting, but they could have been much better with more Screen time and development (Vision was great). The Actions scenes are much better than in the previous movies, but not good as CA2: Winter Solider, it was a bit over the top. My favorite part was the Reveal of Vision and all of his scenes, it felt like "Now this is feeling much more like the comics" because he is an android (sort of ? in the movie ) and differentiate from the other characters.
If I'd give the movie a score it would be 8.2 due to the fast pacing and overbloated subplots, which didn't have any development.
My Scoring for the other MCU movies.
Cap2 - Winter Soldier: 9.3
GotG: 9.1
Avengers 1: 8.7
Avengers 2: 8.2
Cap 1: 8.0
...
ok - good.
I hope AoU get's a directors cut with additional scenes, it really needs it. I'll definitely have to see the movie again on Blu Ray.