Listed below:
No midi DIN or TRS connection.
USB-C takes up the op-z port so if you want to record via usb then that won’t work, but the op-z can power it over usb which is nice.
Midi over Bluetooth seems a bit laggy sometimes.
Feels a bit cheap, but that also makes it light and inexpensive.
Otherwise it is fantastic!
Quick update. I sold the QuNexus. I want knobs and a pad section so I’m using my Launchkey Mini mk3. It works. Additionally, it can be configured via Novation components software. This allows me to make a custom map for the OP-Z. So far so good.
I am looking at buying the Korg NanoKey Studio though. It looks like the perfect OP-Z controller because of the scenes and all around functionality.
Little video of it in use (you can do a lot more with two free hands though 
)
https://www.instagram.com/reel/CkyOIGKA1dv/?igshid=YmMyMTA2M2Y=