I can only speak for the Heroic launcher but this has been my experience:
- One click play button like Steam, but it’s easier to configure Linux-specific settings in the menu.
- Updates are done automatically or can be forced like Steam.
- Cloud saves are available, but need to be done manually from the game settings menu with the risk of user error.
- There is a friends list and chat, but the games I played had their own in-game friends list.
- Unfortunately, no achievements from what I’ve seen.
- No DRM, so you truly own the game. (as far as it’s possible to own something digital.)
- Linux game support seems to not be any worse than Steam
- Built-in Wine/Proton version installer.
I got some weird specialised hardware over USB working via WinBoat. Might be an option for some.