Don't have any direct experience with it, but utilize the basic principle (per my understanding) which is prolongued static holds.
I think it's a good program for people that a) don't want to spend too much time in the gym and b) are looking for a safe environment.
I really don't have any gripes with it at all, but I could never make it the only thing I do because I just plain like to workout more often. I do heavy holds and super slow reps and can attest that they add to strength, I'm not particularly interested in finding THE absolute best way to workout though. I care more about what I actually enjoy doing at the gym, and BBS doesn't do it for me.
Wish you much success with it though!