the best one when i did my research was the logitech one. they are like $40. i picked one up at target a while ago for $30 but ended up selling it because it still didn't feel right. i personally don't really like 3rd party controllers, but the wires from the xbox live headset and the controller tangling was starting to irritate me, so i tried this. however, in this wireless controller, there is no xbox live headset, and the port is on the actual receiver for the controller right near the xbox.
the controller feels good, and is very close to the S controller in size, however my fingers tended to slip off the analog sticks.
i ended up selling that one and getting the logitech wireless headset for xbox live, and now i don't have any wires tangling anymore w/the S controller.