I have just one hunter in one of my instancing teams, and although her DPS is consistently below the mages, she has a number of advantages.

Most importantly, she keeps on doing damage even when I'm too busy driving the tank to actually press my DPS buttons Her pet is damned useful as a second tank too, at least in non-heroics. I first spotted this in Ramparts - Destroyers don't seem to knock the pet back in the same way as they do the tank, for example.

Since they changed the dead zone, I'm quite a fan of hunters in boxing groups now, especially since I solved her "target the next available target when my current target's dead and you're stupid enough to press the shot rotation button" problem!

As an aside, A loooong time ago, I rolled a 4 hunter team (to plug a Priest into later on), but they were universally reviled so I dropped them before level 15. I now think that's more a feature of the Night Elf lands on my server - for some reason they're perpetually full of complete morons - because I had exactly the same experience with my recently rolled NE Druids!