I think the bad rap for Clippy the annoying Office assistant mainly came from a catstrophic implementation choice in the first versions: it was a pimped up modal dialog. So while Clippy looked like window dressing, you were forced to interact with it.
The worst thing about the Metro facade is repetition of that original Clippy mistake: forcing me to interact with it, instead of being an option.
There are also some implementation deficiencies: e.g. getting rid of a Metro app requires keyboard, or a long drag, and drops you back to the start screen, which requires a different method (so 2x Alt+F4 won't do the trick). I often miss a "back" button.
(The AppStore is terrible. Just terrible terrible terrible. It could be good, but it looks terrible, navigates terrible and works not much better. I'd also prefer more editorial content, because I am actually not stoked by the ability to pick from fove dozen tools to open .gizmo, all of which screaming their superiority at me while being mum about their shady business models.)
However, as a UX concept, I quite like The Style Formerly Known As Metro. A well designed Metro interface is smooth, inviting, clutter-free, and lets the actual content stand out.
Visually, it is certainly an improvement over the window glassgloss and colorful-blob-of-something icons growing more and more dysfunctional. (e.g. we had to replace button-style radio buttons with actual radio Buttons, because the pressed state is almost impossible to distinguish on most color schemes. Same goes for list selection without focus - on cheapo LCD's, hard to tell; had to add a rectangle around the item to stop the complaints.)
The Windows 8 desktop has some minor welcome improvements, otherwise it's a vanilla Windows 7 - i.e. good. The start screen works identical to the old start menu für keyboard jockeys, so I didn't mind at first. Right now I'm trying some replacements, e.g. Pokki[^] is a great example how good a metro-based interface can be if done right.