St. Vincent (early stuff is really really good)
Lead guitar dude from Blond Redhead uses 2 I think.
The last album of Adebisi Shank is like 99% pitchfactor, I love it! Too bad they are dead.
It's a great pedal. I tried it for 10 minutes and I was astonished, I even said to myself "I want two!", and I was only using HarPeggiator.
I replaced it with an H9 with Crystals, H910/949, Synthonizer and HarPeggiator. I didn't care for the other regular pitch shifting algorithms, I guess I'm not a pitch/octaver/whammy guy.