Im not sure as to how many studios use Linux, but I suspect it wont be many, with most studios wanting support for their current systems (MAC OS and Windows). 3D World did a quick article on the trends in studios between MACs and PC that was covered in issue 101 or 102 (I can't remember), and tbh this is a never ending argument for most MAC and PC users.

But the short answer is they both have their good points and their bad points.

As for linux, well those users really are in a niche with there own user set, maybe someone here knows roughly how many studios have a linux system the use for development, I think more than likely Linux/Unix is used as a backend or middleware system for file storage or even render farms.

Why does Linux run faster? Easy Windows has so much gubbins tied into it that it takes a good chunk of RAM to even get up and running fast enough. Leaving you 12Kb to use for your renders :p

Linux/Unix has less resource overheads when its running freeing up processor and RAM for more important tasks.

linux is a good OS tbh, but its lack of formal support can be an issue, or if you go for support via Suse or Redhat then you better get you wallets out.