I went with the Dia-compe rear brake on my 3Rensho at first because it seemed keirin "correct" but it doesn't really have any serious stopping power. I think track riders use them just to make their bikes legal on the road. I finally got the front brake adaptor (actually a set with a cheap Dia-compe brake) and added a Shimano Ultegra brake. Now with that and rear leg braking, I feel confident I can stop in just about any situation.
