Horror stories and heaven stories, you can get an earfull of both. Some people who are already in a group are flashing on the good and bad times. There will always be bad times to be had along with the good. Chances are, 'yes'. I can't think of a author alive who couldn't benefit from a good writing group.
Chances are, 'maybe'.
This is true of even the best writing collective, because eventually they will tell you what you need to hear. A good group will admonish your mistakes gently until the day comes they lay the word on you. Maybe you'll be ready, maybe you won't. The truth can be devastating. The ones most adversely affected are the writers who do not distance themselves from the work.