I use the M9 with an acoustic guitar for looping and also effects, so have built a midi pedal to handle the looping side of things, so the M9 always in “effects” mode. The real beauty of DIY mdi is that you can customise the midi messages to use the device exactly as you want.
I want to capture a chord sequence then immediately stop, then when I replay the loop I want to be in “solo” mode (requiring 3 pedal presses), so the custom code triggers the echo & delay on the M9. At the end of the solo, I want to go back to live guitar, so stop the loop & switch of the effects. So the pedals act as follows
#1 switch between overdub & play
#2 switch between play & stop
#3 switch between play with overdrive/delay triggered & stop
#4 switch between record & play
I’ll live with that for a while, but can change the midi messages relatively easily. With a couple of other pedals I could, for example, reverse the loop, or swap between 2 scenes.