+1.
one night my rig was making a funny noise.... the bar manager where we were that night can play... so he was playing while i was trouble-shooting. he's not a great player, not awful either... but that's not what mattered... has a very different touch than me. and when he stepped on my zendrive... holy crap it sounded great.... i can't get it to sound like that.
This is the case for all pedals, and all amps, and all guitars.
I sold two relatively expensive amps locally on Craigslist. In both cases, the guys who bought the amp sounded darn good when they came over to check them out (and buy them), but I couldn't get a OD sound I liked out of either one of them.
The Zendrive works well for me. Not perfect, but I really like it. I can certainly see how it would be all wrong for someone else.