From what I hear for most people Windows 7 worked very well for DAW purposes (whilst being vastly faster for general or gaming use) which is vastly different from my actual experience of it on my particular system. It started out "ok" (notice "Ok" and not excellent) and gradually degraded over time to essentially be a stuttering, audio dropping mess on my particular system. Stranger still that this was happening despite not having actually changed any of the setup or workspace resource requirements from when it had actually functioned in a barely acceptable "OK" kind of way. 
However having tested Windows 8 METRO for DAW use (on my particular system) in various preview builds I was completely blown away by its consistent rock solid performance as a OS base for DAW use. GPU rendering was vastly faster and smoother without even the slightest hint of any of the same kinds of GPU rendering problems, audio pop, stutter or drop under base system load that my system was suffering from when using Windows 7. 

Windows 8 RTM final release build has been out since the first of this month for developers with MSDN subscriptions, however I've still not personally managed to get my mitts on a copy.

It seems for everyone else that have bought new systems post June of this year, they can actually acquire a legit copy of Windows 8 for $15 with prior advanced registration of their new systems around early Octoberish. For all others? Well its a little bit more but nothing in the regions of what we've seen in the past. The $200 to $500 pricing structure depending on which version and where you bought it from has now been thrown out of the window and essentially a thing of the past. Its full price for general consumers is now penned in as being as flat as the land of Tulips across the board come October at $40. I liked that very much. So I'm definitely looking forward to finally getting a permanent fix to all my DAW woahs when it finally lands for general acquirement. Lets just hope they don't mess up and put out something completely different to what was going on in the preview builds as far as pure system performance is concerned. In the sense that lets just hope its not slower in any way, although there's nothing wrong with if they actually make it even smoother and faster for final release. 

The 1st of September sees the roll out of Windows 8 via Windows 8 Volume License Re-sellers for volume license customers without Software Assurance.