To be clear, Win-P is an old keyboard shortcut (it lets you switch monitor output -- I use it to disable my second monitor when I want to play a full-screen game, and enable it again when I'm done), it just has a Metro look now. Win-Q is insanely useful, though, pulls up search and you can just type the name of the application you want.

Metro in Windows 8 was entirely useless for desktop use, especially multi-monitor use, Metro apps could only use one monitor at a time (so you couldn't run, say, the Netflix app on one monitor and then pull up the Start menu or the Metro version of IE on the other) and putting multiple Metro apps on the same screen was clunky at best. Windows 8.1 made this much better -- you can put multiple Metro apps on a monitor, and run Metro on all your monitors at once. You can even run a mix of Metro apps and the desktop on a monitor, so you can run a Metro IM client in the side of the screen and have Word up in the rest of the screen. There's such a paucity of Metro apps right now that I haven't found much use for this, though, but if there WERE Metro apps I wanted Windows 8.1 makes it possible to actually enjoy working with them.