I shave it all. So does she. Her skin is super sensative, so if I don't keep the bush gone, she gets all irritated (and yes the same holds true when we were unshaven, or any combination). I figure that since I'm already getting rid of the hair on my pubis, the ball hair better go too.
So for me at least, it equates to significantly more sex, and ever so occasionally a blowjob, which I never ever received from her before shaving.