Just got back from the 2am showing...had a blast. The 12am and the three shows after that one sold out, so I was hoping I timed it right when I chose the 2am showing. Turns out it was just about perfect...had plenty of room in the theater, only about 30 or 40 people in there. It's not often you get to see the biggest blockbuster of the summer on opening night with most of the theater to yourself With too few people it's not as much fun, so it was just about right.
As for the movie, it was a great ride. I have to give Joss Whedon credit...he did a great job. The running time is 2.5 hrs though, so with previews it ends up being close to 3hrs in the seat, so if you tend to get antsy sitting in one place for so long, be forewarned. I had heard someone say in a review that one of its strengths was how Whedon got all the main players enough screen time where it felt very balanced. I definitely agree with this and no matter which character you want to see most, you'll be happy. The plot isn't as involved as something like The Dark Knight, but it's not "surfacy" either. It felt about right, and the few times when I was JUST about to think it was slowing down too much, Whedon throws something in there to make sure you're still right there with him. I thought Ruffalo did a great job as the Hulk and Robert Downey Jr was fantastic. Also, this is probably the best looking film I've seen in a while...the CGI was very realistic and the action scenes were well done overall.
Is it a GREAT film? I'd have to see it again to make that call. My initial reaction is 'no', but I don't think it set out to be that. But it's certainly worth a trip to the theater and it's a lot of fun. I do have one question for the comic nerds here if someone could PM me the answer to this question. I will use spoiler tags to protect the innocent: