Windows 8

Nothing wrong with Win8. It is fast and stable.

The problem is the new interface (Metro UI).

You spend a hell of a lot of time finding out where they have hidden all the stuff.
Getting used to OSX is probably less demanding.
Will become probably as popular as Vista.
Win 8.1 makes it a bit easier to get the standard desktop experience.
Win 8.2 is rumored to bring back the start menu.

 

Audio wise everything remained the same.
No support for UAC2 (USB Audio Class 2).
This USB audio standard is supported by OSX and Linux from mid-2010 on.
If you want to play > 96 kHz over USB you still need a third party driver.

 

The only real new thing is offloading the audio.

According to Microsoft

In Windows 8, the audio engine has been redesigned to work with audio streams that have been offloaded to a hardware device that is separate from, but connected to, the computer's main audio system. This is referred to as hardware offloading.

This requires third party hardware.
Haven’t seen any product supporting this yet.

References

New for Audio Drivers - Mircosoft