I love seeing new interfaces being applied to music, it's like being introduced to a new instrument for the very first time. It makes me want to jump on and play with it and see what I can make.
What's great is that it's so simple and it just makes sense. The visual cues are fantastic and I love all the different variations available - time based, trigger based & scanner. The collaborative nature of it is also a great feature.
Let me know if you guys see any more music related interfaces!