Norman, I can't comment specifically about the Revel B12, but I do think it can make a big difference how the sub is connected into your system.
The REL approach, bass reinforcement, is designed for truly full range speakers and then you still have the problem of multiple bass sources in the room which may interact negatively. Using this approach with non- full range speakers will simply increase the distortion produced by the main speakers. There are also issues with building crossovers using speaker level signals rather than line level signals.
The bass replacement approach can be used with any speakers from mini-monitors to full range. The idea is to insert a line level active high-pass filter before the amp for the main speakers. This removes the bass load from the amp and speakers, which lowers distortion. It also leaves a single bass source in the room, which may be easier to deal with.
You may find this article of interest:
http://www.mkprofessional.com/bass_mgmt.htm-- Bob