I played a fretted Zenith today in GAK. I was disappointed.
Body finish looked nice but I was less keen on the feel of the neck - had a cheapish feel to it, whatever that means, but sort of reminded me of 60s and early 70s Japanese stuff.
I played through a Markbass combo and at first was suffering from some crackling/rattling - I wasn't sure whether it was the combo, the bass socket, or the lead but either way it didn't help - but seemed to right itself after a while.
The action wasn't bad but I think many people would want it a little lower which, with no bridge adjustment other than filing down the saddle, would probably mean a neck shim.
Sound was pleasant enough but the difference between the magnetic and piezo pickups was less than I'd hoped given that having those two options available would be my reason for buying the bass. The feel of the pots was feeble and I suspect the electronics are the real weak spot of the bass. The blend control seemed to run quite unsmoothly from piezo to mag and back.
I'll be going back to try out the fretless version when they have one but my experience moved me from 'maybe a fretless Zenith would be nice' to 'I doubt if I would buy a Zenith'.