Finally gotten a little quite time to have a play, first thought's its pretty special. The size of the kit and the polish of the whole experience is really getting up there to the it just works Mac level, you press the steam button the pad to wake the console and tv from sleep then you're pc gaming in seconds, a bit like the power of the switch experience. Much more of a rapid get in there and get on with it than the Xbox series.
Getting into the cube yesterday and switching the NVME was easy with lots of well thought out design choices meant you could get to it with a few screws and then sliding the case out. Think it's only a little more to get to the ram as well (but didn't fancy going that far just to see if there's one stick or two).
Little gripe was getting the Steam OS re-immaged to the NVME, but that was because it wasn't clear to hold the power button till it goes purple to get it to boot to recovery mode. bit of user error there was it was late after beers trying to work it out, but my Mac brain wanted to hold a button combo and my pc brain wanted to go to a bios, neither remembered what to do with the deck but it wasn't a worry. Amusingly the Bazite install from the BC250 worked pretty well, even if it wasn't what I wanted.
The power of the eco system getting downloaded content from the deck to the machine was seamless, picked everything to install, went to bed, woke up with all games installed and shaders sorted. Couldn't ask for more

need to try steaming from it across other devices next just for the fun of it.
Finally the controller is also flat out amazing, it has a really nice shape and weight to it, the stick feel really direct and precise to what you want to do and the buttons just feel great to use. Played Ori and Hollow Knight as platforming tests and it just gives some real confidence that what you want to do when you press the buttons is going to happen. It's that little bit nicer than the 8bitdo pad (which is also really good). Need to try out something that'll let me use the track pads as I love those on the deck.
All in all, I'm well happy! Still waiting to see how long till the mrs notices the change in things under the tv as well...