I'm sure it's nice. And what makes it nice is that it's integrated. But it's really not "new." Almost the same functionality could have been accomplished years ago with two arrangers MIDI'd together, or even an arranger and a MIDI song player with "mark-and-jump" functionality. Yes, it would take a little effort to get it set up but you could bank your favorite progressions as songs (or non-transposing style tracks), with different time signatures. Just an imaginative special case of general functionality that's been there all along.