My absolute favorite thing is that it runs Linux. I love being able to ssh into my Steam Deck so I can back up save files, tweak game configs, and just generally do whatever the hell I want with it. I've been running Linux exclusively for 6-7 years now, and anything that doesn't let me easily get a shell via ssh just feels suffocating. I do all of my file management in a shell (absolutely no graphical file managers, I can't stand them), so the Deck feels like a natural extension of my desktop and laptop with Linux and ssh.

My least favorite thing? Probably the screen. I wish it was brighter. I'd love if SteamOS implemented some burn-in mitigation, because I feel like that would greatly increase the chances of an aftermarket OLED panel being a thing. I know there'd still be some major hurdles (do OLEDs even work with LVDS/whatever protocol is used to push pixels to the Steam Deck's screen?), but a bright, clear, punchy, replaceable OLED sounds great.