John
They are the same OS in many ways. I came from Vista and didn't have any problems adapting to Windows 8. I did get a Kindle book "Windows 8 Inside out" that explained most of the things I wanted know. For the Windows user it should feel familiar. It is not radically different. The Start Screen may work for you or not but it is a nice way to access programs. I bypass it with an add on free start menu called Classic Start Menu that lets you work the way we did with previous versions. But don't think that the Start Screen is something to be avoided. Its not. I just prefer working this way.
With Windows 8 you also get the ability to run "metro" apps.
What Windows 8 offers the DAW user is a more efficient OS with better audio handling and improvements in nearly every area.
Its just a better OS.
I agree with John and he is correct!
There are no drawbacks about Windows 8 x64 only benefit when it comes to performance and security reasons.
I'm personal still on Windows 7 x64bit Ultimate and it works perfect with SONAR X2. If I build a new computer today I would Install Windows 8 x64.
It seem that any "program" that work in Windows 7 will automatically work in Windows 8. Even XP program works.
It seem that even Windows 7 drivers work but that can be tricky though.
There are possibility that Soundcard drivers and other hardware doesn't work in Windows 8 still if it run and work perfect in Windows 7. So you need to check your hardware and drivers are supported and work in Windows 8 too. 9 of 10 it will!
Programs like SONAR X2, Cubase 7, Spectrasonics, Native Instruments, Nomad Factory, Waves, iZotope, EastWest, Vienna and many other have Windows 8 work and are support already.
Best Regards
Freddie