One of the things I find most interesting creatively about the M13 is the expression pedal. There are very few limits to what you can do creatively with it. You can control various parameters on different pedals simultaneously. For example gradually add in the mix from pedal 1 (let's say fuzz) and reduce mix from pedal 2 (let's say synth) with 1 pedal/movement. Then add a 2nd pedal and it becomes crazy/possible what you can do with this thing. As far as sound quality, I A/B it the M13's equivalent of the EHX Big Muff Pi with the actual pedal and it was really, really close.