I ended up grabbing an upgrade copy of this over the weekend -- my dad got a new laptop on BF and Metro kind of grew on me after playing around with it a bit. As a launcher, it seems a lot nicer-looking and easier to organize than the Start Menu or desktop. And I could see myself using apps for a few things like Netflix or Twitter; I expect it'll be nice to get that crap out of my browser and into a more native interface.
Some parts of it still seem pretty clumsy, but I feel like I should give it a fair shake at least. Worst case, I'll just install the third-party Start Menu replacement (though honestly I never use that thing except for search anyway).
And for what it's worth, my dad has been super impressed with it so far. He's been using Windows pretty much since the beginning, but now he's mainly wanting to do some light browsing, email, etc., and it seems like he'll be able to do most of that without leaving the Metro interface.