If you want the mount and pet.. sure. I don't really use the mount anyway. I think you also get some SC2 portraits and a Diablo banner but that might be with the CE only.
The mount is -eh- at best and the pet looks (quite literally) retarded, with it's facial expression.
If you want to do it for the mount ok, if you really really like it, but don't do it for the pet.
Thanks for all your help guys, I think I will just leave it then... as a little side post what are you guys opinions on medium and high pop realms and pve vs pvp