I haven't read any posts other than the OP, so excuse me if I'm saying something over again.
Windows 8 in my true opinion is a more touch and tablet based OS. Anyone who says it gets better performance is a bit wrong, I run Windows 8 and 7 at my workplace on the computers customers come in the build and the difference in hardware usage and performance is not enough to make your decision based off of. Unless you plan on getting a touch based monitor, I wouldn't go with Windows 8