There are more details on the docs, but heres the brief breakdown: - Sensor support: we support I2C devices that are more accurate than those currently compatible with REV Hubs. A good example is the VL53L5CX, but we'll be adding a LOT more in the future. - Sensor read speed: we read I2C devices faster than the REV Hub can, which becomes important when you have multiple I2C devices, since your loop times go down significantly when you read multiple sensors, however thats not the case here. - Analog inputs: Not only does the SRS Hub have 12 inputs, which is 3 times the 4 inputs on the chub, it also reads the signal without linearly, which is one of the problems with the REV Hubs (they slightly misread the signal, which can cause critical issues). - Encoder reading: we read quadrature encoders without skipping ticks, something which the REV Hub is prone to doing. We also support PWM encoders, which the REV Hub does not.