Hi,
I'm from "the dark side", i.e. FSX. I would recommend not to use Windows 8. As an OS it is not yet mature and for us simmers to whom tweaking is bread and butter, Win8 is a nightmare.
IMHO there is nothing that can beat a good Windows 7 64 bit install. Windows 8 may be great for tablets and phones, but not so for Desktop PC's. At work we were given an evaluation copy of the latest Windows 8.1 by a Microsoft tech consultant. We tested it for a week or two now and discovered that you cannot even install M$ Network and system management tools on it. Before you ask, yes we did have full admin rights on the rig.
So we're going to skip Windows 8. It is IMHO the new Vista...
Take care,
Dumonceau