I bought the X1 sometime in Janurary and a couple of months later, people said they couldn't hear me well enough. There were also some other problems, like the connector from the headset to controller not fitting right and it's too big if you want to use the X-Plorer guitar (if you talk to people while playing GH2). Btw, the X2 will also have these problems. It's not completely wireless, it's just like the regular 360 headset where you have to still connect it to the controller.
Edit: For the person who asked about the X1 - it's wired, so it has a USB cable to connect to your Xbox 360 (also includes a USB extension cable) and it has cables from the headset for game audio on it. It's basically a mini-plug with a RCA adapter extension if that makes sense.
Overall, I went back to the regular 360 headset because it was too sweaty, the mute button isnt located on the connector to the controller like the 360 headset (which you'll miss when you don't have it), and it started to pad down my hair too much on the top of my head :O !