Hey,
Just got mine in the post this morning, so I thought I'd do a mini review for you all.
Cost me £12.99 delivered which isn't bad at all. The receiver itself is tiny (approx. 8cm x 4cm x 2cm). Average build quality; plastic and not very heavy at all. Comes packed with a driver CD and some manuals:
The software is not bloated at all. Just seemed to install some drivers and a tiny applet as far as I can tell. It starts up one new service (XboxStat.exe) which uses up a constant 10MB of RAM. I can confirm that it DOES work on Windows XP x64, which is ace! Once it's installed you can plug your Receiver in to a free USB slot and the green light should ping on:
Connection is pretty straightforward; turn on your controller with the "X" button, press the button on the Receiver, then press the connect button on your controller. After they sync, you can press the "X" button to bring up a tiny little status app that shows the controller's status: