In any comparison you have to examine the parts. That includes, but is not limited to belt, deck, treadmill motors, electronics, rollers and frame. These are the major components, and comparing their quality will give you a good feel as to how good your treadmill is. In particular be aware of the listing of the motor. There are no standards to grade treadmill motors by, therefore some claims may be excessive.

Regardless, you want to compare motors that are rated as continuous duty.  What is continuous duty? Continuous duty horsepower ratings are the amount of power a motor will produce “continuously” at a given RPM (revolutions per minute). Continuous duty HP is the “working power” of a treadmill motor, providing constant power to the drive belt.