Anyways, I loved it. As others have said, there's some bits I loved, some bits didn't really work, but damn there was so much to cram in, and overall I'm satisfied.
My only real nitpick complaints are that the final battle could have been a bit longer, and maybe given everyone more moments to shine? I feel like a few characters didn't really get any moments in there. What did Bucky do besides turn up at the start? Or Groot? Drax jumped on a guys back for all of two seconds. And what did Hulk actually do?
And also as someone else said above, man, during that line up moment I'd have loved to have seen the Defenders, Agents of SHIELD and even the Inhumans in the background.
Still, when all was said and done, it was a great film, and holy fuck at "Avengers Assemble". It's one of those moments you wanna burst out into tears, joy, laughter, just everything!