Absolutely, completely, utterly what you would expect from an Avengers movie: big, loud, brash, big, hokey, cheesy, predictable, big, funny, preachy, spectacular and above all, big. Everything is turned up to eleven and that's just as it should be. Some of the fight scenes are shot so much like a music video - with the shot changing every second or so - that it's hard to keep up sometimes but actually, it turns out that keeping up isn't necessary anyway. Much like with the first "Thor" movie, the 3D was completely immaterial: I barely noticed it was even there, although that might just be a reflection of how blasé I've become about the technology already. All in all, though, the film was never boring and I enjoyed it really quite a lot.
The next lot of Avengers look like a load of fucking pussies, though.
It's fine. I liked it a little less than Tonks. These movies are like Bond movies: They are as good as the villains. Ultron was kind of meh. Actually, Scarlet Witch was a bigger emotional foil. For a while.
I don't think I've ever had a movie fit my expectations so perfectly, for good and bad. It was perfectly acceptable.