Pivotal isn't really a bug tracker though, is it? It's more for tracking project tasks. On some projects, these might be similar things, but when you have a large QA team and customer support teams, I don't think it's going to cut it.
It just depends on the process you put around it. Our team wasn't huge - ~13 if you include QA - but effective use of labels and "task" state management made it great.
