My only concern when I bought the GML was the most PWM make the motor humming at low speeds, but GML is offering 30 money back and 5 years warranty so if someone is offering that , is just because he knows what he is doing....my home made pwm was working good but its high frequency buzz (humming) drove me crazy.
GML has momentum and brake...agree is more expensive but have a great customer support and warranty.
Andre.