Picked mine up a bit earlier.
For R900 this thing is very impressive but has some deal breaking issues for anyone with a more high-end setup.
The quality of the packaging and device and remote are very impressive for a R900 device, I prefer using this remote to the POS remote that comes with the Nvidia Shield. It's running Android 8.0 and the interface is very smooth and haven't really noticed any issues with responsiveness. The set up experience was also very easy.
The biggest issue I have is that audio passthrough doesn't seem to work, at least over HDMI (I haven't tried SPDIF), enabling it in Plex results in garbled audio and in Kodi it seems to just ignore pass through even when enabled.
The box will output HDR just fine too and it has settings in the options for various HDR<->SDR conversions. When playing an HDR video through Plex it gets stuck in HDR and you have to restart the box to return it to normal, still have to play with it more to figure out what's going on.
Another big issue is that it cannot do 4K in Youtube at all.
For people with 1080p screens and no surround set ups this things is awesome for everyone else I'd probably spend more and get a Shield if you want a properly supported Android TV box.
I've only had a few minutes with it so I'll fiddle with it tonight and see what else I can find (will try and side load Netflix).