The OP-Z was an absolute mess! That thinkpad bullshit they used to mold it from had curing issues that they never quite sorted out. Had one from the first run, wouldn't stay on or charge without a vice grip. They sent another one that also was not square/did not sit flat and suffers from intermittent shorts, attempting to use the pressure sensitive top button is a coinflip on it turning off. It's also quite colorblind-hostile, and is impossible to use outside or under bright stage lights. Needing an app to manage it was such a dumb choice. It definitely had some neat pre-MIDI 2.0 ideas but in practice most of what it offers is better handled further up the chain.

The OP-1 (and TX-6) on the other hand are excellent, I have 3 of them and love them dearly! Plenty of producers and bands still use them to great effect, the used price is evidence of this. Treating it as a controller is a pretty solid sign you've missed the point. Most midi devices are not able to cope with the bpm/playback speed shifting in response to the tape interactions (which is fully in spec). I did appreciate people offloading them for cheap.