Top of this list used to be particular versions of Ubuntu
Summary: GNU/Linux "market share" in Steam grew by a quarter this past year, boosted by SteamOS perhaps, but watch the trends in distributions; even the Ubuntu-based distros aren't near the top (and SteamOS moved from Debian to Arch, so expect Ubuntu to stagnate further)
If IBM cared about quality rather than alleged "cost savings" (cutting corners), it would assign more IBM staff to Fedora, but instead the exact opposite happened, with the likes of Cotton and Miller removed from the project