- very big and heavy
- button placement is very bad (as a result of the size)
- steam software is just bad, slow and resource intensive (it's basically a web browser powered by chromium)
- not every games are compatible
- not every games have controller support
The Nintendo Switch is imo a better handheld console, it's the perfect size and you know you can play every games released for the switch, so you are not gambling
Valve control the Steam platform, and yet they can't enforce Deck's compatibility, worse, games that worked can end up not working anymore [1]
I don't own a Switch, i'm still waiting for a proper Switch alternative/successor, hopefully Sony will decide to revive the PSP
[1] - https://twitter.com/gamingonlinux/status/1596824471670648832