bb7 has outboard pad adjustment, bb7 has spring tension adjustment, and most importantly bb7 has diff pad with like double the surface area they have the rectangularish ones not the round ones like the bb5s have
either way the bb7s do feel better, they are considered the best mechanical caliper
i'd also recomend gettin some decent levers to go with if you don't already have, fr-5 or speed dial 7s (or w/e) the fr5 is like 15 bucks for the set, and even bb7s feel like crap with crappy levers