@Spearchucker Jones
No, I have no MS Axe to grind. I like Windows 7 and use it on a desktop with multiple monitors. I generally have multiple windows open, mainly with reference material or research I need to produce a document, presentation etc. or reading documentation in one window whilst programming in another.
The "Modern"-UI makes a lot of sense on a tablet or a very small screened notebook. The apps I've seen so far don't seem to make much sense on a multi-monitor 27" desktop. For example, in Windows 7, I have Solitaire open in a corner of the screen and play a couple of moves whilst waiting for another task to finish. In Windows 8, it is full screen and the graphics (at least on the preview) seemed to be rendered for a small, low-resolution screen. Having huge poorly rendered playing cards taking up a complete 27" monitor was ugly and looked stupid.
The Contacts app was similar. In Outlook, I can look at a contacts details, whilst writing a letter etc. In Metro the "card" takes up the complete 27" screen and is pretty useless. At best, I could split it 2/3 1/3 with another app, still not very useful, it only needs to take up a fifth of the screen, at most.
I like Metro on my Windows Phone 7, it works very well. The Start Screen works well in Windows 8. But not being able to resize and move the apps around on a multi-screen set-up is a huge leap backwards to the days of MS-DOS. As I said, Metro / Modern UI makes a lot of sense on small devices, but it doesn't make much sense in its current form on the desktop.
Some applications, like Lightroom or video editing suites, which tend to be used full screen, even on large displays, might benefit from the simplified interface, but I don't see it being a benefit with a majority of the applications I use today.