I'm currently working on 4 hunters (lvl 68 now). The BM pets gets so damn insane, so I skipped my intended 1 MM, 3 BM.
Been playing instances with a resto shammy friend. I have three gorillas for the stomp and one wolf for the howl. On packs with lots of mobs I got focusmacros for everyone so I can split them up and tank individually, and if they are more then 4, one of the gorillas will manage to hold aggro from the healer with only thunderstomp.
With the increased healing taken on the tenacity pets, healing gets very easy. Don't got my hopes all that high for heroics thou.. (allthough, I didn't think they would hold aggro/survive in normal either :P).

This ended up slightly more Off Topic then intended, but to sum up my point: Go BM/BM, it's amazing!