I just picked up an X4. One thing about this pedal that I don't think is obvious from the docs/internet reviews: Although you can use the delay function & the looper simultaneously, in other words, you can record a loop with a delay, and then overdub a part w/ different delay settings, the preset and tap tempo function is lost when the looper is active, which kinda blows. Not only that, if you use tap tempo to set the delay time, once you engage the looper function, the delay time will revert to whatever the time knob happens to be set at. Useless in a live situation. My idea is to hack together a small box w/ an arduino, etc. & a tap tempo stomp switch to generate a MIDI clock, which I'm hoping will allow me to toe tap the delay time regardless of the X3 looper mode. That's a horrendous oversight on the part of TC, I can't believe I'm the only guy that would want to loop/overdub a delay-processed signal AND be able to set the delay time w/ tap-tempo on the fly.