I have them.
They're very nice. If you've only ever used a default MS headset, then you're in for a HUGE surprise. Seriously- headphones will completely change the way you think about gaming. They enhance the experience SO much.
They're nice. There's a little small for my ears, so they fit very snug. They won't hook up to your computer, only your TV. I bought it, then a month later bought the X12's. The X12 lets you hook it up to your computer, has 20mm larger speakers, and blocks other sounds much better. If it isn't too late, you might consider dishing out the extra $20 for the X12's. I'd recommend it, since I have both.
But if you aren't willing to spend the extra $20? The X1 is still a solid investment that will do wonders for your gaming experience. Plus for me? If other people are sleeping in the house, I can blast the game volume through my headset and just turn the TV volume down!
:D