The reason the B5 is less than the others is because built out of NOS parts! It is the most genuine of the old style REs because it is using the old frame and such. I really don't expect it to be available very as they run out of parts for them. It was the one I wanted originally, but they weren't available when I was. Went for instant gratification and got a G5, instead.
Wasn't disappointed, though. But I wouldn't have been disappointed in the B5, either. Nice bikes.
Bare