of differences and similarities between the two, I would favour the Bumble Bee (Presumably that's what you mean by BB!) Let's face it, the sharp edges on the bezel & case are part of the DNA for the RO/OS series and I'm sure we all agree that once you get that nick/ding on the edges, some of the appeal are lost. Personally I can't stand the sight of a ding on the edges of shiny surface. Worse yet, once damaged, there is almost no cure aside from the replacement.
As such, the forged carbon case comes in handy as the ding/scratch/mark are all hidden well from the 'dirty' finishing of the case hence making the watch so much more wearable.
Obviously it would make a difference depending on other factors such as what you have currently or had previously, collectability etc etc but I guess only you can decide on these...