Avengers sounds like the best line-up (at least if Wolverine was out of there). Why is it not going over well with those who aren't enjoying it?
For me it's because we were promised a return to classic Avengers and instead got nothing like it at all. Besides the fact that people who ARE NOT ON THE TEAM are getting more panel time than those actually on the team, it feels like Bendis is pulling a Mark Millar, coming up with an "awesome" idea then trying to top it with another one until the comic becomes this ridiculous thing that shouldn't even be part of the main MU.
As for why I dig Secret Avengers, it's the closest out of the 4 titles that feels like Avengers. Plain and simple it's the one that is giving me the classic Avengers type style and action.