I have never really used a pedal tuner. I have a tuner on my M9 but it sits in the loop. I dont think it tunes properly either in the loop or when there is distortion in the path. A good example is when I tune my Gretsch G5120 with the M9, it never sounds right. So I recently bought a headstock tuner. Best investment and it was cheap. I was amazed at how quickly I was able to tune my guitar and to have it stay in tune. With headstock tuners available and cheap, why do players still use tuners on the pedal board?