Having used Windows 8 Server in a Fusion Tech Preview 2012 VM for the last fortnight with no issue whatsoever I decided to take the plunge and format my main desktop (productivity/gaming) Windows 7 machine to Windows 8 Server, too.
Can happily report this has also been relatively painless (only exception has been the need to manually specify INF for some drivers – autodetect based on folder & driver setup programs sometimes unreliable which speaks only to the fact I am installing Windows 7 drivers on Windows 8 and nothing about the quality of the OS).
Can’t say the same for Mountain Lion in “production”. Finder crashes allthe time (for those of you only Windows literate, Finder is the equivilent to explorer.exe). Nuff said.