Here's my obvious newbie answer to your obvious newbie question --disc brakes stop NOW! I tried out a bike when I was test riding a bunch of different ones that had discs on it, and WOW, they were really different. I squeezed the brake levers with the amount of force I would have for regular brakes, and nearly went over the handlebars. Ok, that is a bit of an exaggeration, but those puppies really worked, that's for sure, and I did pitch forward some. I kind of liked them, once I got used to them, but the bike I ended up with has regular brakes on it.