I guess I'm contrarian when I look at all these high ratings but what ever.
The plus side is that there is more time with the 'characters' this time around as they're already "assembled" and the action scenes and CG is well done but that is all it's going to get.
The movie is long, really long - despite there being a gaping editing hole already. You still could cut an hour off this without loosing anything important though. It's depressing how something this shallow has been blown up like this.
How great is that we're getting superheroes instead of some other generic action movie. Let's just do all the standard stuff with CG anyways. Some yadadada in some slave country, a trip to Manhattan, South Africa and lets not forget a derailing train action scene in Korea. It's also quite dumb how random the powerlevels are in this (not that the group makes any sense like this anyways).
The big bad? The more he opened his mouth the worse it got. No one said anything about a degenerating A.I. His plan was shite and so was the execution but otherwise someone had to actually write a compelling story that is more than action sequences (or beepbeep to quote Black Widow). You better not be poking for holes in this as it's littered with them.
Too make matters worse the ending was actually the worst part. I don't think we need 20 scenes of them saving a family from the 10th floor or a lady out of her car when countless other people get fucking crushed. A sleazy guy like Stark is already the most popular one of the assemble anyways so why would anyone need confirmation that the guys are not evil? The fighting goes from one-shotting robots en masse, punching them a lot and even drop-kicking a single one - these guys sure are effective (it's amazing how much attention those copy paste robots get). I'm really glad tho that Captain America's spidey senses can feel the "waves" they're attacking in so he can do more drops.
Too bad the Marvel's circle-jerk isn't going to stop anytime soon (with Disney joining in). I rather have the other ones back because they do not get hyped like these movies so I can ignore them more easily. I wonder how many directors more they're going to burn down the road.