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.