My boyfriend and I have this. I like it because it's made of non-porous material, and it's rechargeable. You can re-use it a lot more than the jelly rings that uses bullets operated by watch batteries.
Personally I am not a big fan of vibrating rings in general. I wanted to experiment. I hate porous material and watch batteries. Lelo bo then became a very obvious choice.
The vibration from bo is not very rumbly, it's pretty buzzy. It's more of a tease during intercourse. We don't use it often though.