I had both, and was able to judge them together. I was using them onstage, not using them for their amp simulations or to record via a studio mixer - maybe someone else can offer an opinion there. For me - the Zoom had instant patch change (no muting between changes), had a better tuner, and was small enough to go in the back of my amp (a MusicMan). The Digitech had a slightly 'jumpy' tuner, but contained a 'modelled' Tubescreamer. I bought this because I was so impressed with Digitech's Bad Monkey pedal, and the tubescreamer setting was pretty close. I found the Digitech was slightly easier to program. For the delay, chorus, phaser, reverb settings etc., I didn't find much difference. I'd just about decided that the overdrive meant that the Digitech was the winner despite the jumpy tuner, then found a setting on the Zoom ('modelled' Marshall Guvnor pedal) which I loved, so kept the Zoom.