from a performance point of view, I like to use MIDI to control my devices (change patches etc) but I like the idea of having the backing track nailed down to a finished audio file. If I just play along with MP3s, I lose the midi control of my guitar and vocalist processors. So what I'd like to see in RB is way to predefine a list of SEQ files that will play in order so I have the advantage of embedded device controls along with the MP3