The patch that adds Kinect voice functionality to Skyrim was released this morning. I had the sound up pretty far on my TV, and the game still had no trouble recognizing my commands. The only hiccup is that you need to hold down RB to use the shouts in the dragon language, though you can use a dragon shout in English without pressing a button. So, for example, you can just say "Unrelenting Force" and your character will use the strongest version of it, but if you want to say "Fus Roh Dah," you need to hold down RB. It's a minor issue, and would only really matter in that you'd need to hold down RB if you only wanted to use "Fus," instead of the full "Fus Roh Dah."
The quick menu, sorting, and skills commands are all nice additions to have and work pretty much as you'd expect. By far, the follower commands were my favorite as you can easily tell your follower to attack an enemy, grab an item, wait, move, or trade items much easier than going through the clunky dialogue options.
Bethesda put out a PDF that lists all of the commands. It can be found here.