I'm very interested in his technique but still very new (7 months) to practicing BJJ. Being that flexibility is one of the few physical assets I have I feel like I should learn more about his style down the road - but I'm going to need someone in front of me demonstrating and correcting my fuck-ups. I thumbed through Mastering the Rubber Guard at Barnes and Nobles a few weeks back - it looks about as well laid out as a book can be, but I don't have a training partner anywhere nearby (have to drive 60 miles to get to class as it is)....and I don't think my fiance' would appreciate being subjected to sloppy gogo and twister attempts.
For what it's worth, the subject of Eddie Bravo/Rubber Guard has come up in discussion several times from my classmates and they all (mostly white to purple) seem fairly open to it - or would if they had the chance to train it. Never did hear my instructor (bb) chime in one way or another.