Mostly works quite well.
I had a screenlock/energy saver privacy issue involving an HDMI connected an Acer GD235HZbid 23.6". This was quickly mitigated by retaining screenlock but disabling power save. The monitor would go into a locked screen but eventually show a slightly corrupted copy of the actual workspace that was visible while unlocked after a couple minutes.
I have not attempted with other monitors or monitor connection methods.
The only other problem is the NUC has a singular USB BUS, so I'm limited in doing things with I2C/non-block USB devices inside of VMs without compromizing dom0 in some way or another. This is probably my largest detractor as a developer to use this hardware/OS combo for various research. I was able to study the topic enough to understand that there are kernel memory implications involved and that it's trickier to compartmentalize non-block USB devices for attachment to VMs. USPIP/VirtualHere and other options came to mind but I did not want to short circuit the security aspect.
Hope this helps.