I remember the day very clearly when I got my nice mtb setup with hydro discs. You see all the warnings about how responsive they are. Nothing really prepares you for the slightest one finger pressure causing the wheels to almost lock though. Took some time but once you get used to the small movement required they provide a serious amount of stopping power for almost zero effort. I got the v brakes on my other commuter almost as good (in the dry with cool stop salmons) but I still have to say those hydros are my favorite - just not so useful on ice. You don't want to stop fast on that!