Steam Controller was significantly better than Xbox controllers for some kinds of games, but it was much clunkier for others. Steam Deck's controller is an improvement over either of them, and this new Steam Controller appears to be pretty much Deck's controller without the Deck, with some tiny extras added.
The Steam Controller is amazing for first person games. I set the right pad to quick mouse movement with some inertia and the gyro to precise mouse movement, and it feels so natural and pleasant to use.
I have six of the previous generation controller and I love them, only minor annoyance is pairing them occasionally. I don't really use the haptics part all that much though
I have a 8bitdo controller and they are really good. They work perfectly with Debian 13 and probably pretty much every other distro.
https://www.8bitdo.com/ultimate-3-mode-controller-xbox/