So many features. So versatile. Midi In / Out, Audio In / Out, SD Card, USB Host, reprogram with PC on USB.
An open source wonder. Use easy to understand blocks and connect them together to create complex instruments. The software automatically connects to the hardware and installs your instrument patch. You can manipulate the controls in the software in real-time and later transfer that control using external hardware controls.
Robust User Community
An amazing, helpful group of people. Questions about patching, hardware interface, enclosure design, sound / audio are answered within the vibrant user threads. It's really a model of open source sharing and expanding of the ecosystem.