I have been going to one (a specific bipolar one) but I have stopped as my schedule became hectic and traffic was insane. I have mood issues but other things are more in play, so I was not identifying with BP1). I am planning to go back because it was nice and useful (I am(was) relatively newly diagnosed) and when it was very fresh and shocking the group helped a lot. It is worth a try.
P.S. I was thinking of a 12-step group to try, I am not to drink and have some issues 12-step is perfect for. Maybe better than a therapy support group.....