Riding around on a road bike after being on a mountain bike is a pretty neat feeling. So much less drag, way better pedaling efficiency, more gears, more places to put your hands.

But if you ride on a lot of crappy pavement you'll immediately notice that mtn bikes are way more comfortable and cushy, and to some degree just more comfortable all of the time. And the brakes just seem like they're in a much more convenient place as well, I hate the brake lever placement on road bikes.

No matter, if you ride any kind of long distances road bikes are the way way to go. So much faster.