Gravity DC Micro Metal Gear Motor w/Driver - 30:1

These little motors and ESCs seem to work very well for little robots. I am using them on a 1 pound combat robot and they generally have held up well in testing. I did however see one big impact when my robot hit a wall hard enough that killed one of the motors, although the ESC and gearbox seemed to be fine. I am running them with a DC-DC buck regulator at 7 volts, any higher than that and the ESCs seem to die.

Pro: very practical package. As simple as it gets. To take into account: small reduction: fast and little torque. Make sure it fits your expected regime. Cons: when changing direction suddenly under loads something stalls. Motors loses power and reengages a second later. We suppose is some countercurrent protection tripping in the controller, but don't know for sure. Changing direction smoothly (first slow down, invert, then ramp up) sidesteps the issue.