I don’t know if I count as an “informed opinion” but I switched my existing Honeywell thermostat for the TH8320ZW.
From a wiring perspective it was super easy, I just made a note of which wire was connected to which terminal (i.e. G,C,R,W,Y in your picture) and then connected them to the same terminals on the TH8320ZW. Yours appear to be color matched (yellow wire to the Y terminal) so that makes it even easier (it been over a year since I did mine so I can’t remember if mine were that way).
The trickiest part was the programming. This is so the thermostat is communicating correctly with your HVAC equipment (nothing to do with the z-wave). Prior to disconnecting my old thermostat I printed out the manual to the new one (I can’t remember if this was included in the box but here is a link: https://customer.honeywell.com/resources/Techlit/TechLitDocuments/69-0000s/69-2486.pdf ). I went through the settings on my old thermostat and found the correct settings in the TH8320ZW (Pages 7 and beyond) and made notes.
Once I physically installed the TH8320ZW, I just went through and entered the settings I had written down. I confirmed that the thermostat was working correctly with my furnace, and pairing it with my original z-wave hub was a snap. When I moved to SmartThings, I had to unpair it from my old hub and then pair with ST. Again it was a complete snap.