About the quilts and the RRs; I've been able to fit my JRB quilts to my RR. You're right that it isn't an ideal fit, but it is certainly functional. There is just some extra quilt there that isn't needed/used, but there don't seem to be any gaps or issues with the quilt performing just fine. I've got 14+ nights in mine with JRB quilts so far.
I still haven't put up my formal review, but I'm really being swayed by the RR. It is a very comfortable hammock and the views are simply second to none. If I have a complaint about the Blackbirds, it's the wall of fabric on my right side. The RR removes anything and everything that restricts your field of vision in a hammock. You like stomach and side sleeping and the RR will provide that much better than the BBs.
I think that gathered end hammocks are more flexible, but can't really point to any one aspect of them that would validate that thought. I will go on record saying I believe gathered ends to be more idiot-proof simply because the RR (like any bridge) relies on those spreader bars. I don't trust spreader bars because if they fail, the hammock is much less practical. Those bars are an extra piece of gear and they are fairly critical. One sleepy tug on that bar above your head in the wee hours and it will be a long night. Speaking of flexibility on the plus side, I think the RR provides the best hammock chair of any hammock currently on the market; including my Trek Light/ENO style rigs. Seriously! The back support when seated is just spot-on!
Still, those RRs are very comfy and honestly, existing gear can be used with them given a little creativity. Some minor mods and you wouldn't need to be creative. If I had to make the choice today I'd probably go with a RR and buy a Traveler as a gathered end option.