The one with added colour just looks fantastic:
That's the closest fit to true Metro styling I believe. The few coloured icons may deviate from that a bit, but if Metro mandates that all icons are monochrome then that's a design flaw IMO (I don't believe it does). This is especially true for tiny icons.
I'm less concerned with Metro as a principle design concept for the desktop the more I see modern examples, what I am concerned about is MS's past approach to the little details in its interfaces - history has shown that's lacking. Metro *really* needs you to pay attention to these small details as it can have a massive impact on the final presentation as the above image shows. Just a lighter shade of gray, better scroll bars and some slight font changes results in something that really looks professionally done.
It's almost there, but I hope MS considers these tweaks to the GUI for the final release. The image above is to my eyes, about as close to perfect as you could expect for a Metro "inspired" GUI.