Great popcorn fun!
It's a great, fun, and mostly family-friendly content. There is a whole bunch of geek-gasms in this movie, from Hulk fighting Thor, to Thor fighting Iron Man, to Iron Man fighting Captain America, to Captain America's Shield against the Mjolnir hammer, and Black Widow vs. Hawkeye. This is really a great film that sticks to the Avenger's roots. (minus Wasp and Hank Pym) This is a great, action-packed movie. The actors did a really great job in their roles and I really think they deserve a "Bravo!"
These following are the small little errors and/or problems I had with the movie. First, the plot isn't very exceptional, but mainly because this is a more "turn brain off explosion" movie, and it did extremely well in that category, and even got involved in the story at moments. Also, I think the movie didn't build as much character development into Tony Stark/Iron Man as they should have, and when he "sacrificed" himself, we didn't care as much as we could have. I personally believe Agent Coulson's death was more emotional/tragic than Iron Man's fake death.
A must watch summer flick, and a must watch comic book movie. It's really good, and the CGI is perfect, and so is the breathtaking action!