1. LENS MOUNTThe lens mount is different: RF for the R100, EOS M for the M50 II. Lenses designed for the R100 won’t work on the M50 II, and vice versa.
2. MONITORThe R100 has a fixed rear LCD with no touch sensitivity.The M50 II has a multi-angle touch screen that you can flip to the side and rotate 180˚.
3. DRIVE SPEEDThe R100 has modest continuous shooting capabilities: 6.5fps with One-Shot AF, and 3.5fps with Servo AF.The M50 II is faster: 10fps and 7.4fps respectively.