Minor thread hijack: I use Koolstops on one of my bikes, to get the cartridge holders I ended up upgrading my brakes to Ultegra- since it didn't cost that much more than just buying the holders (the original callipers weren't very good anyway)
I've got some pretty good deep-drop brakes on my commuter- anyone know where I can get fairly cheap cartridge holders so I can use Koolstops on that too?