The Duet 2 provides fast motion and quick processing via a 32 bit processor. All that processing power means you can also expand your machine to include many more stepper drivers. (additional expansion boards may be required) Firmware is stored locally on a Micro SD card and can be accessed via the web interface for easy modification. Connections to all other hardware components is easy with vertical molex connectors or screw terminal block for secure connectivity.
The Duet 2 WiFi includes a baked in WiFi chip for easy machine control from any device on your network. From computers to tables and smartphones, printer control is available across the board. Having stepper drivers baked in is great - but they aren't just any old drivers. The TMC2660 drivers are crazy quiet and capable of up to 256th microstepping for smooth and precise machine motion.