I am seriously underwhelmed by the Windows 8 UI. Watching three different design languages pass by in less than 10 seconds just screams of bad Ux, if not outright laziness.
Now, the Metro UI makes plenty of sense for a phone or a tablet. The human finger is sensitive and nimble, but let it never be said that it's an especially accurate pointer. This is why large icons and big tiles work so well on MIDs. Metro is not my personal preference, but it's an approachable and creative take on a modern tablet interface.
My cursor, however, is not a finger. It doesn't need 150px of padding between icons, or huge tiles, or cards, or anything else that works well for a tablet. Trying to scale the tablet UI upwards for a PC--and doing a frankly terrible job of trying to hide the legacy UI behind the glitzy curtain--is as miserable as trying to scale a desktop UI down to the tablet level.
It's the same mistake Microsoft made with Windows 7 tablets, except in reverse, and I want nothing to do with it.