I'm developing the Falling-Up Robot, a very tall balancing inverted pendulum bot, using the Teensy 3.6 microcontroller with the Arduino IDE 1.6.12. I want to learn feedback control systems through practice & experience. It's tall so I can interact with it from my desk. So far, the brain and chassis is in place, and the basic balancing control system is in place to keep it from falling over.
See video: https://www.youtube.com/watch?v=Xmt67HTI2Hg&feature=youtu.be
I used stepper motors to take advantage of high torque at low RPM and zero backlash. This allows very steady stand-still performance. Dealing with the stepper-induced mechanical vibration was an issue, but was solved with analog filters on the IMU and an Extended Kalman Filter in software.