My 37G cube is BB on starboard. The rockwork is just two towers zipped together. I had to move 3 months ago and it was relatively easy. I wish I could have critters who need sand sometimes, but all in all I am very happy with it. I do get some detrius build up - but it moves to only two spots, so easy to clean. For flow I have 2 tunze nanos and sometimes a Koralia 3, Deltec M600 skimmer, no sump, no top. The bottom is just about covered so you really can't tell it is bare anymore. I like it, my next tank will be BB too. I will try to get a fts soon.
btw - lots of people say that reefs look more natural with sand, but some of the best diving I have done was in Saba - just off St. Maartin. There is no sand on the island and always clear, so bb could be considered 'natural' or at least naturally occurring in limited instances.