I had a feeling that the Linux version would actually run faster. I can't put my finger on why that is though. Valve says it's because of the underlying effeciency of the kernel.

However, I'm still very much concerned about the things that come with proprietary games on the Linux platform. On the one hand it will open up Linux for a lot of users but then again I want a fully free platform without any DRM drenched material or proprietary code. This is what made Linux so powerful in the first place.