Looks cool. If I start gigging with a PC it'll be because I want to run MIDI Guitar with a Roland pickup so I'd still need something more capable as an interface - GP10, GM800, SY1000, etc. At that point, I'd rather just use one of the existing machines I already have.
I get the appeal of this though. It'd be great for a lot of situations for guitar, bass, vocals, drums, and/or keys.