We saw it in 3-D, because Mrs. Orbert made the reservations and didn't realize that it was a 3-D showing. In general, I avoid 3-D because I wear prescription glasses, but apparently they've made some decent advances in 3-D tech the last 15 years or so because it rarely bothered me and even enhanced things a few times, quite noticeably.
It was pretty freakin' amazing. So many characters, introduced individually or in small groups, unusual subgroupings, and each getting at least something reasonably interesting to do. That can't have been easy to balance. Ha ha, balance! Anyway, I thought that that aspect of it was very well done. And as others have said, even with all that, they had time for some character development, lingering shots, and even plenty of fun banter, each appropriate to the character(s) in the scene. Very well written, and again it can't be easy to write for so many different characters and different styles.
I'm not surprised that the end credits seemed to last like 20 minutes (I'm sure it was closer to 10, not sure by how much) and of course some people didn't stick around for the post-credits scene. Seriously? How many Marvel movies have you seen, and you don't know that there can be one or more "extra" scenes? I've heard some people say that they avoid them. Why? They're not spoilers as such. They're actually small (and sometimes large) parts of the legitimate overall story.
Anyway, it was a pretty good flick.