I didn't hate it, definitely didn't love it, to use a quote from
I didn't hate it, definitely didn't love it, to use a quote from <lj-user=Phoenixshadow> "I was...whelmed." With the exception of the Hulk none of the characters were done particularly badly (though I actually really enjoyed most of Bruce Banner's bits in the film just not big green himself) and the plot wasn't bad per se it just didn't really come together for me.
As much as I hate to say it I thought that Joss Whedon was really the weak link in the film overall. I thought some scenes would have been very good if not for the somewhat forced cutesy Whedonverse dialogue (which was in some cases fairly cringeworthy) and the film tried too hard I felt to be self referential though to be fair that could have been a side effect of the fact that this is the only team movie in comic movie history where all of the main characters had been in their own solo feature films. Still even with that being the case I thought that another director could have smoothed that out a bit.
Mark Ruffalo as Bruce Banner I thought was one of the better performances in the film. He was a very different Banner than we've ever seen especially for film/TV but I thought it was an interesting read on the character. Aaaaaaand for the few minutes after you first see him change I thought the Hulk was done well. Then there's the rest of the film where the Hulk has "become a team player" (and I'll say no more for fear of spoilage and I forget how to do an LJ cut) where I found Hulk to be really annoying.
I wanted to stab Hawkeye in the face but I have wanted to stab Hawkeye in the face since I first encountered the NGA (not Green Arrow) as a nipper so in that regard I can say that Hawkeye was done very well too. The rest of the film as I say, I didn't hate or even strongly dislike I just didn't particularly love it either.