Now I have minor (?) problems with ultra cheap Chinese motors which fell off, and are choppy even with intense micro-stepping. Yes, you guessed it : they are low quality :D
On the video you can see the robot itself, and the app which controls it. First I blink one of 4 LEDs mounted on the robot (each controlled separately), and then I drive the robot. Each motor is controlled by a slider, and it is very difficult to go straight with this kind of controls, but easiest to implement.