I've pretty much palmed off any work today and sat here setting this little beast up. The joys of WFH.
So far I've got ES-DE set up and played some DS, 3DS, Switch and Dreamcast and I have to say it's been faultless with the few games I have tried, albeit only short bursts on each game just to check them out. 3DS and NDS games running at 4x upscale look fantastic. Crazy Taxi at 1080p 60FPS is a joy to play on it

Switch has been ok, had problems with Mario Kart 8 (probably need to muck around with the settings), but Mario Odyssey and Wonder both run at pretty much locked 60, with a few dips here and there as shaders compile.
I've also managed to get it networked to my pc which makes transferring files over so much easier, can even send wallpapers from Wallpaper Engine over to it.
Had a quick play with Gamehub and a had look at Balatro, Stardew Valley and Circuit Superstars all of which ran at 60fps (or very close to). They are hardly demanding games but it's a welcome addition to have my whole Steam library at my fingertips.
I think I need to get a grip though. It's not too bad ergonomically if you're just using the face buttons but once you need to start using the shoulder buttons as well I can see it getting a bit crampy (but I do have fairly big hands, so ymmv)
Overall I'm super impressed with it so far. Left the fan set to Smart and haven't heard it once, but I'm sat next to my pc and laptop so might be different in a quiet room after a long session. Can't wait to sit down and actually play some games properly, there's a whole load of 3DS games I missed out on that I'm really looking forward to getting stuck into. I'm sorely tempted to take it on holiday but I've already had "The Look" from the Mrs so I think I'm best off leaving it at home