The two biggest differences between these encoder types are the environment in which they can operate in, accuracy and resolution. Magnetic and inductive encoders can survive in very harsh environments, whereas optical encoders cannot. Optical encoders, like the MicroE product line offerings, have ultra-high resolution, whereas inductive and magnetic max out near 21 bits (2 million counts/rev). Magnetic encoders generally have lower repeatability and lower accuracy, and are sensitive to nearby electrical and magnetic fields.
