I have very little invested in comic characters, and pretty much anything I do have invested in comics is DC, and mostly Batman, but I enjoyed the Iron Man films enough that I'm looking forward to this. I'll get caught on Thor and the Cap, but I've heard that they are basically just there to set up the Avengers movie.
Being a shallow, thrill-seeking peon who likes explosions and shit, I don't have any issues if liberties are taken with any of the characters - I probably wouldn't notice, anyway - so as long as it's not too schlocky, they at least try to purty-up some of the most blatant Hollywood clichés, and don't use CGI for explosions that actual explosions could do better, I might even go to the cinema to watch this