Maybe it’s just me, but I find pitch shift effects to be Zoom’s weakest area. On guitar, as well as bass.
None of them really float my boat...
In certain context I've been able to get along fine with the pitch shifter/whammy. What seems to be necessary is to use a post-effect to seriously roll off the top end and add distortion in various amounts. Some of the drives work great for this. Frequency limiting the pitch shifter helps immensely, though I'll admit it's not the greatest pitch shifter out there. I've gotten a very usable "Killing in the Name Of" guitar solo pitch shift out of it FWIW.