I have installed Windows 8 Enterprise in a Parallels 8 virtual machine (VM) on my Mac Pro. I give each VM 4 CPUs and 4 GB of memory. I still have my Windows 7 VM configured with the same resources. The good news is that Windows 8 is noticeably faster, both in booting and running. The Windows 8 Windows Experience score I get is 6.9 vs. 5.9 for Windows 7.
The bad news is that the now user interface might be great for a tablet, but it sucks for a desktop machine with a 30" monitor. Without the Start Menu, which has folders, everything is a total jumble:
As you can see, I installed Cygwin, and every X application is listed in a huge information-poor rectangle. Yes I can drag them around, but I need folders to hide most of these. And already, I have to scroll my large desktop to reach all of these icons. It is just as bad as OS X Mountain Lion's Launchpad, which now has 18 screens to scroll through!
Even worse, the four corners are "hot." If you mouse over to them, they display menus. The one at the top right is key to doing anything, and it expands into a panel along the right border of the screen. But for me on a large monitor, it is very difficult to mouse downward in a straight line so that it does not stray out of the panel. If you do stray, the panel closes and you must start all over again. What an awful user interface! Brian Boyko has a really funny video about the futility of the interface.
You can get to the "usual" Windows desktop, but you will then find that the Start Menu is missing. Fortunately, Classic Shell comes to the rescue. It restores the Start Menu (in any of its incarnations) and brings you to the classic Windows desktop when you boot. So, all of the Windows 8 interface ugliness issues disappear. Yeah!
I can now actually use Windows 8 and am enjoying its improved speed and security.
But there are many compatibility issues that arise. Norton 360 V5, PerfectDisk 12.5, and CorelDraw 5 all claimed to have compatibility issues when I tried to install them. But you get no clue as to what the issue is. The beta version of Norton works properly, but I still have 304 days of protection remaining on my old V5 subscription!
Actually, I found out that Norton has free version updates if your suibscription is active! It is in their menus somewhere.