I installed it under VM Fusion on my Mac, and it's absolutely awful as a desktop OS. I had to install mouse drivers. Mouse drivers! PCs haven't had to deal with that since early DOS. And the driver package left 5 new icons on my metro panel. Such clutter! And if I remove them, the file system is so masked that I don't know where I'd find them if I needed access to them at some future point.
Also like DOS, there's no multitasking. At least, it's almost impossible to tell from the metro interface what's running. I find navigating within metro programs to be extremely difficult as well. I'll give this another few hours of experimentation, then it's going in the proverbial trash.
On the plus side, it's making me use my Amiga more!