It has its ups and downs. It crashes a lot and games will sometimes just stop working after an update. And I can't exaggerate how frustrating it is to look online for some support and all I can find is someone saying the solution is to trash it and buy the Aya Neo or Rog Ally. But I had a similar issue pre-SteamDeck where I'd look for support on a PC game and someone will say that the fix is to buy it on console, so this is just a case of history repeating itself. Ugh.
But I love it more than not for sure. I've beaten more PC games on Steamdeck than on an actual PC. I love finally having a no-bullshit portable PS2 emulator after years of only ever having these "sorta kinda but not really" ways to play PS2 games on the go. I love the trackpad for point n' clicks and I love the gyroscope for shooters. Also I like it when a game will say that it's not Deck supported but then I play it and it works fine from start to finish. Overall it's a damn good device and I'm glad that it led to the development of a few competitor handhelds. They'll probably never be as affordable as those crappy hundred-dollar AndroidOS boxes that can barely run Dreamcast, but they've got a great niche nonetheless.