Leszek Godlewski, the developer behind the Linux port of Painkiller: Hell & Damnation, gave a talk a few months ago about bringing games to Linux. The presentation was given at the Digital Dragons 2013 European Games Festival, but the slides and video recording are available and are quite interesting.
The presentation covers Steam on Linux, positive and negative traits about Linux, what Linux game developers need to know about Linux, and much more. The Farm 51 views the engineering costs of a Linux port now as being "low" for an already multi-platform game, SDL has served to their advantage, and the Steam Linux Runtime is quite useful. At the same time, Leszek recommends using Ubuntu for doing ports and following whatever actions Valve does when in doubt.