Thanks Jason. Your comments echo what I thought when I tried it out tonight at GC. Not a contender for me, overall. I might take a look at the new Zoom B3n and see what's happening there.
I have an original Zoom B3 and MS60b. They are both very versatile and usable pedals, but have some limitations that I don't jive with 100%. I still use them for certain applications, but the M series works better with my ears and workflow.
My thoughts on the Zooms:
Dirts are brittle and sizzly like many digital devices, usable only with eq.
Comps are better than Line6, but too squishy for my tastes.
Filters sound way fatter and better voiced for bass, the M Filter and Z Filter really stand out.
Synths sound fat and good, but the tracking lags just a little too much to feel right for me.
Delays and Reverbs are good, but tap tempo requires an external device or input, and that doesn't jive with me.
Mods are more usable than the Zooms because almost all have a blend or hipass option.
Octaver is decent, but not impressive.
Pitch shifting is horrible and basically unusable. Unless you want a glitchy warbly out of tune sound (maybe sometimes?).
On the B3, the Bit Crusher is a hidden gem. It sounds great and gets 80% of the awesomeness of my Mobius Destroyer. The other 20% gets lost live anyways, and the Mobius does 1000 extra things I'd never apply to a bass track.
Numerically, it would seem the Zooms beat Line6 for me; but I'd still grab the M5 or M9 first. I use enough other pedals to overcome their shortcomings, and the M series interface is more intuitive to my workflow.