Every single parameter (every single rotary knob) can easily be sequenced via MIDI and every physical knob can in turn send MIDI to make this an awesome MIDI controller. No sub-menus or parameters hidden behind LCD screens. Everything transparent and clearly laid out. The flexibility to create anything from bass drums and percussion sounds to searing melodic sounds, to strings, pads, synth basses and everything in between. All with a delicious analogue sound quality that would be an insult to present to anybody knowing anything about electronic music. It's the perfect companion for Reason.
The lack of MIDI out was annoying at best in the past but now that Reason 6+ can actually record the sound of gorgeous, external analogue hardware back into audio tracks it's just ridiculous.