Awkward key combination, and not available unless the desktop is in focus (meaning not available in Metro or if you have any windows open)
2. Charmbar (or win+c), settings, on/off, shutdown
Too many clicks/mouse movements, and the charmbar is awkward to show without the keyboard. This is the best option right now, but it's too much.
3. Log off and use the menu
Takes too long, having to wait for the log out, then get rid of the welcome screen, THEN shut down.
These may seem nitpicky, but when my old option was "Winkey, Left key, Enter" (which could be done in less than a second, and with my eyes closed), or "Click, then click two inches to the right", anything more than that, especially when it requires the mouse, let alone as much mouse travel as it does, or requires that the desktop has focus, then it's enough to want an alternative.