when I was inpatient I had to attend group therapy, and I really didn't like the roleplaying that the therapist made us do while in group. On the other hand, before I was diagnosed bipolar, I attended AA for a number of years and benefitted from that (after I was on a mood stabilizer no more urge to drink, period; lucky me).

A lot of what you get out of the group will depend on the group, and what you're willing to put into the group. It's okay to sit on the sidelines and just listen for awhile.