Re: Sleep - Compared a traditional console, the Steam Deck does not auto-download updates quietly in the background while its asleep/docked. That is my one gripe with it. You need to have the screen on and active for it to start downloading games.

On top of that, the default behavior is to stop downloads while playing a game. You can change this in the settings, but at a significant performance hit.

Re: The 'just works' - In handheld mode, all Steam Verified titles have 'just worked' for me. Docked mode is a different story, because no game has automatically switched resolution automatically. You need to set the Native resolution mode on a per-game basis.

Additionally, there is always a chance that an unverified game you're looking for will not work very well on the Steam Deck - be it control-wise, graphically, or some other reason. It is not as 'plug and play' as a traditional console, but the device continues to get better over time with updates.

Yes, if you're in the store page, you can look for an icon that confirms whether the game is verified for the Steam Deck.

https://www.steamdeck.com/en/verified

If a game works on Proton (http://protondb.com/), it will almost certainly run on the Steam Deck. And the Steam Deck UI does a pretty good job of highlighting games that run well on the Deck and telling you what the compatibility issues are, if anything.

Assuming the game itself runs fine, usually the main issue is mapping steam deck controls to the in-game keyboard and mouse config. I find the UX for doing this to be pretty confusing and terrible (doubly so when using an external controller), but this is helped some by the fact that you can apply controller mappings submitted by other Steam users.