Are you looking to buy a tiller from a member, or are you asking for recommendations, based on your tractor model?
If it's the latter, I run a King Kutter 48" on my B7100. Some said that it wouldn't be able to power it, but I've had no problems. The only consideration was weight- the tiller is heavy enough that I put suitcase weights on the front. Even then, it is a little light. But, it handles it, and I've tilled quite a few gardens with it over the years.