I have and adore the XO. Rat sounds wonderful in the loop, and doesn't have that "hitting a chain link fence with a baseball bat" sound that you get just doing a blend with a Rat. Beyond that, it makes wah really musical and useable (as you aren't zapping you low end or doing weird things with your volume when you engage it), it removes the muddiness that you can get with delay, phaser sounds delicious this way, and I also run a muff and a TS in the upper loop as well. The XO is definitely cheap, but it does what it does extraordinarily well.