Have been using this ( [...] ) in my home office since the start of December and I'm very happy. Worked perfectly out of the box.
The Xbox 360 is definitely faster connecting to Modern Warfare 2 games than with wifi, and finds games faster too.
The only difference I've noticed from using wifi is that downloads from the Internet are the exact same speed but the network monitor I use shows tiny gaps as if the data was being sent in huge packets with tiny fraction of seconds of space between them. I can't explain why that happens and it hasn't affected download speeds or online gameplay. I can definitely recommend this.