Update 2:
Zoom B6 came. Spent few hours with it yesterday.
Some first, brief feelings (more than actual thoughts):
* yes, it is compact (duh!)

My #1
* looks to be a keeper - most of my points check out
* no major “oh no!” moments, so far;
* packed with good FX. “Good” = both, quality and usability. Covers my #3,3a,4,5
* awesome concept: 100+ models of actual, single-function pedals (or amp/cab sims); each - tweakable (virtual knobs etc.); combined into mini-boards (“patches”) to make usable sounds.
* spot-check: the trackers don’t glitch (octaves) - yay!
* it will take time to explore all it has to offer. My #2a is definitely covered.
* my #2 (single-stomp): not exactly; or I have to discover how. Don’t see yet if I can assign entire patches (=FX combos) to a single button. So far: looks more like scroll-to-it (using buttons nevertheless).
A minor bummer

bypass engagement:
Everything else behaves like “light is lit - the _thing_ is ON” - e.g. an effect. Bypass also behaves like that, but the result is confusing (to me, at least): when it’s ON (lit) - FX are out of the loop, sound is clean. So the lit up FX say “we are doing!” while lit up bypass says “no they ain’t”. Overall: I’d rather see no-lights board as “all clean, nothing ON” and some-lights as “something was added”.
Will get used to it, I guess.
Cuteness: sounds of my youth. A patch that sounds exactly like synth intro to Beat It. Now I _must_ play it! And tell the keyboardist: “Don’t worry, I got it”
Next update: more impressions.
Please look at the top of this thread to refresh - what I was looking for.
My impressions are coming from that place - what I specifically wanted; not "is it objectively the best pedalboard?".
* Money well spent: yes. What B6 (objectively) packs and (subjectively) gives me looks to be worth $500+.
* Gig-friendly: yes, pretty much on all of my original a-must list.
* The good: one-stomp capability (stomp once/twice - you got entirely new complex sound for next song). Yes.
Some details below - to help understand how this works for me.
B6 organizes sounds like this:
- 100 models; all: individual pedals/amps/cabs/IRs. So you got this pool to combine into...
- Patches. Patch = up to 6 models, in sequence of your choosing. 4 out of 6 can be assigned to stomps, for instant ON/OFF (note: I wish all 6 could be assigned at once, but B6 does not have enough real estate for all 6. A good thing: there are often FX that you might prefer to have always ON - e.g. comp/pre-amp - so no separate stomp is needed for those). A Patch is equivalent to an actual mini-pedalboard. Patches combine into...
- Banks. 60 memory groups, each holds 4 Patches (to the total of 240 Patches). When you're looking at a Bank - each of 4 available stomps instantly selects a Patch. This is my "switch from pedalboard A to pedalboard B" in one stomp.
* Patches - limits exist.
The expected thing: B6 being a computer must calculate your FX in real-time, and can get overloaded if you're asking it to calc too much simultaneously. Some FX look to be more compute-intensive than others.
The good thing: B6 tells you, at the point where you are composing your Patch, how much compute power each FX wants (%-ge), and what's your Patch total demand on computer.
The inevitable thing: it will refuse to add a new FX to your Patch if your total exceeds 100%. So there might be some compute-heavy combos that you may desire but won't be able to do with B6.
The Zen: so what. I'm gonna hold my go-fancy impulses in check.
* The not-so-good (I've not seen many multi-FX that do it differently; except the ones that allow navigation/scroll by turning a knob - that would be faster): navigation b/w the Banks. Either screen-driven up/down arrows or the same but by clicking stomps. No "search by name/number" capability. Oh well. Planning to write a cheat sheet with names/locations of my fav Patches. Or for gigs: will make my own Banks with Patches I want, and put them next to each other in memory, so the switch takes 2-3-4 stomps at most.
* The stupefying: options and combinations. A lot! Each model (pedal/cab/etc.) also comes with virtual knobs as the real things do. The variety to be gotten from myriad of possible combinations is overwhelming to me. But - fits the original ask: I'm happy to do homework and pre-spend hours dialing in the "right sounds" that can be instantly recalled.
* The extras which may not be so useful during live gig (perhaps useful for recording though): amp/cab/IR's. IMHO no one will appreciate the subtleties added by those when I'm playing live; people will hear "dirt!", "chorus!", "wah-wah!", and will feel the overall effects of comp/pre-amp. Nevertheless - B6 has those which is good.
* Ergonomics. Feels right, so far (disclaimer: no live gigs with it, yet). Details:
- Size.
Wasn't looking for put-me-in-my-pocket. The opposite, actually: playing live I want the unit big enough so that I can see what's ON (with my eyes almost 6 feet away from it), and do not accidentally stomp on 2 things at once.
Requires a separate carrying bag - happy to do that; got Gator that fits nicely side-by-side the B6 and its extra expression pedal:
Gator Cases G-MULTIFX-2411 Padded Utility Bag for Guitar Pedals, DJ Controllers, Micro Synths, and more, 24.5" X 11.5" x 4"
- Sturdiness. Body is plastic; does not look flimsy. Will probably not withstand as much as a metal casing will. Good enough for me.
* FX quality. Must admit: I don't have the most sensitive ears and am likely to miss some subtleties.
This said: spot-checking the staples (comp, pre-amp, dirt, filter, chorus, octave - all in diff flavors) so far made me happy - good, believable, usable sounds, very comparable to my board with actual pedals
(that includes EBS's etc.). E.g. at least one of the octavers - BASS ANALOG OCTAVE - tracks well at G; that's respectable! My EBS Octa does that; many others that I tried choke much higher (as well as just glitch across the entire range). Dirts sound authentic; so do modulations. All in all: satisfied.
* Tweak-me-on-the-fly. Not that I plan to, during live gig. But if anybody is inclined so - an adapter (buy it extra) plugged into B6 allows access to the unit's touch screen functions (edit, re-arrange, etc) from an iOS app "Guitar Lab for B6". This is easier than kneeling down to the unit when on stage. The app responds a bit sluggishly but not much worse than the unit's touchscreen itself.
* Synth-iness. Was not after that, really. The B6 does have a few models of bass synth pedals, none of which is Future Impact or Moog or other from those leagues. To me: B6 has enough potential combinations of FX to make bass sound like it's not bass. One of many examples: easily does Chameleon-like sounds (and more); probably will not give you full Future Impact. But will give you a send/return slot in your Patch so you can plug in the actual FI (or any loop of actual external pedals) if needed.
* Looper. Haven't touched yet - stay tuned.