Saw it last night with my son. It was much better than I expected it to be. Action films tend to run short on backstory and character development anyway. Take one and throw in a half dozen heroes and the chances of it having any character or story development get pretty slim. Such movies tend to be non-stop action with little substance. Maybe this was one of those and I just didn't notice. I saw both Ironman movies, Thor, The Hulk, etc. Maybe I brought the character development and backstory with me to the theater. But I know I was thoroughly entertained.
Tim