After reports that Valve had received shipments of the accessory, a Steam Controller review has appeared. Deleted ahead of a likely release date update, a YouTuber praised its responsive dual trackpads. Even so, the price may make it more difficult to discount the Steam Machine.
Notably, Linux support sucks with those. I have one, and you can’t do any of this on Linux through their software. There are ways to do it still though, as you can do with any controller really.
FWIW… Bazzite has full Steam Input support for mine… It even has a picture of my specific controller.