Study grouping is so key. First semester I study-grouped, but last semester I didn't, and I think it showed in my grades. Last semester me and another groupie had personality conflicts, so we all studied on our own.
It makes such a difference to have something explained to you by someone at your level, or to explain something. And your groupies fill in the gaps in your knowledge, the stuff you didn't realize you didn't know.
If you're on the fence about study-grouping, do it. If you have drama with a groupie, form a new group. Don't throw the baby out with the bathwater!