I would say that (in my opinion/experience) turtle is by far the best levelling pet for bm hunter.
Won't say anything about SV/MM as i have only played those spec's endgame.

I leveled my hunter from 70 to 80 using turtle and i can highly recommend using one.
Shell shield (reduces damage taken by 50% for 12 sec) can be a real lifesaver if you or your pet asspulls too many mobs or if you enjoy pulling bigger groups.

Also with turtle, soloing elites/group quests is that much easier.


And let's face it, it's 'effin a turtle! Can't get much cooler than that!


Just my opinion...