In my limited experience I would say that if you are a bigger guy, sleep on your side in fetal or semi-fetal position, just prefer sleeping in a gathered end hammock, or don't want the extra grams... I would go with the BB.
For the rest, there's MasterCard (to buy a shiny new RR
I'm a bit of a side sleeper and bigger (6'2" 220) so I prefer my BB but I also love my RR. I would probably default to the BB except when the RR gives me some benefit I can't get from the BB, in which case I wouldn't hesitate using my incredibly comfy RR.