Sadly, it's pretty clear that if you run these games on Linux your experience isn't going to be as good, and you'll be getting less "gaming value" vs. Windows. We're not talking about a bunch of little indy titles, these are big releases: Borderlands: The Pre-Sequel, Borderlands 2, Tropico 5, XCOM: Enemy Unknown, Sid Meier's Civilization V. My take is the devs doing these ports just aren't doing their best to optimize these releases for Linux and/or OpenGL.
A nice little tidbit from this report: "Unfortunately, Aspyr are currently still unable to provide support for non-Nvidia graphics cards, as with Borderlands 2. This doesn't mean the game won't work if you have an AMD or Intel GPU, but just that you're not guaranteed to receive help from the developer - the current driver situation for non-Nvidia cards may lead to degraded performance." Huh? This is not a good situation.