I actually never worked for Bodhi, so i cannot help you there (I think, you get an elven chain mail+1, which you can loot from your prime target and some other stuff). Working for the shadow guild earns you the amulett of power (protection against level drain !!) and some other stuff, which i cannot remember quite now. And don't forget the Mace of Disruption, when you are in the grave yard.
@fable: ...."And you have to fight the vampires, eventually, just not in chapter 3" I wanted to express this with "In the end there is no difference which side you choose"