I posted earlier about my first mountain bike, a Giant Revel 29. I now have over 100 miles on it, all on paved "trails" and in a variety of terrain. Today I rode on a paved trail that included climbing the front face of a dam. Rides have ranged in length from 5 to 30 miles with most in the longer range.
This bike is comfortable. The shifting is smooth and precise. The disc brakes are smooth with only some squeals under heavy load at low speeds.
In short, I think this is a fine bike that anyone who is looking for a fitness, commuting or trail bike ought to take a look at. Plus, it is relatively inexpensive.