Auto variable frequency (can be turned of), auto-run for eliminating the motor/drivetrain drag brake, adjustable brakes, 20 grams and usually no need for a cap, built in display for easier programming and a PC interface for even more programming options.
I really like the auto run feature, where a small amount of current is applied for a couple of seconds. That's great for stock motors and/or one-ways.
And the auto-freq works, hard acceleration when need, yet very smooth while negotiating corners or preparing for by passing another car...
Rocket Max