When comparing Ubuntu GamePack vs SteamOS, the Slant community recommends SteamOS for most people. In the question“What is the best Linux Distribution for gaming?” SteamOS is ranked 13th while Ubuntu GamePack is ranked 26th. The most important reason people chose SteamOS is:
The OS natively supports Nvidia, Intel, and AMD graphics processors.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Guaranteed gaming compatibility
Has 6 thousand Linux and Windows games that are guaranteed to launch in Ubuntu GamePack.
Pro Native graphics processor support
The OS natively supports Nvidia, Intel, and AMD graphics processors.
Pro Streaming service integration (under development)
Valve is in talks with streaming companies such as Spotify and Netflix to bring their features to SteamOS.
Pro For entertainment, it just works
What media center software do for videos, it does for games (and later videos).
Cons
Con Hard to install
If you've installed Arch you're probably fine, but for those used to simple installs like (Ubuntu to name just one) you should prepare some patience, determination, and painkillers. Good news is, it's getting better (it's very young).
Con Not built around the desktop experience
SteamOS is, first and foremost, meant to act as a gaming console - it doesn't ship with even some of the most basic applications, such as a file manager or image viewer. As a result, using SteamOS as your primary operating system would require a fair bit of work.