Buyers Dilemma: Road Bike or Mountain Bike? Choose this one!!

A look at my new purchase. It's an awesome bike!
Merax Finiss 26" Aluminum 21 Speed Magnesium Alloy Wheel Mountain Bike
Specs:
Frame: 6061 Heat Treated aluminum
Fork: aluminum mountain bike suspension fork with lock out
Shifters: Shimano EF51 21 speed
Wheels: lightweight magnesium alloy wheels
Rear Derailleur: Shimano RD-TZ50
Front Derailleur: Shimano FD-TZ30
Crank: aluminum 1/2*3/32*24T*34T*42T*170L
Brakes: mechanical disc
Brake levers: Shimano aluminum
Seatpost: aluminum with clamp 31.8 M8*60MM
Handlebar: aluminum
Pedals: aluminum 9/16"
Number of speeds: 21
Product weight: 34 lbs
Frame size: 19"
Weight capacity: 330 lbs
Shipping package size: approx. 55" L x 8" W x 30" H
Model# MS008700BAA