Steam Deck: The comprehensive Ars Technica review

A loooong article that goes really in depth so read it for the details. I'll put up, from the end of the article, the good, bad and ugly:

The good

No portable console has ever had such killer joysticks, and most other buttons are up to their caliber.
Built-in gyroscopic options, 3D audio add some next-gen hardware sparkle.
Relative openness with Linux means you can expect compatible apps to work in the background in a pinch.
Mid-grade games can run on a full charge for a little over six hours at decent brightness.
When a game simply works as advertised, Deck can turn around absolutely impressive 30 fps and 60 fps performance.
Deck's base $399 tier is an incredible value for its power and build quality.

The bad
...but that price point is low in part because Valve skips an install of the gaming-friendly OS Windows, and Deck too often struggles to parse games through its Wine compatibility layer.
Want to get your favorite game running on Deck? Prepare to tap around a mix of in-game menus and Deck's system-level toggles to either maximize power or battery life on a game-by-game basis.
When a game doesn't work, you might have to flip through menus—again, on a game-by-game basis—to troubleshoot possible problems like Steam Deck's buttons being incorrectly mapped or a Steam Deck element randomly freezing.
Valve cheaped out on Deck's 7-inch LCD panel.
Grip buttons, rumbling motors feel like an afterthought.
Deck owners may find themselves juggling microSD cards just to maintain a solid portable game library.
Despite Deck's power efficiency, it can only last so long when demanding games rev to 100 percent power.

The ugly

When your favorite game glitches, crashes, or fails to boot.

https://arstechnica.com/gaming/2022/02/steam-deck-the-comprehensive-ars-technica-review/