The Xbox 360 Color Accessory Pack (wireless controller, play and charge cable, and rechargeable battery) keeps you in the game when your battery runs out, so it can be a virtual lifesaver. I cannot count the number of times that we have used controllers for hours and hours of gameplay just to have the battery die at a key moment in a game. When I connect up the play and charge cable to a controller, it is relatively painless and lets us keep on playing while my battery recharges for more wireless action. Oh yeah!
The cord is plenty long to still kick back on the couch comfortably and play on, and it does not interfere with gameplay while connected. These units are especially useful during a long game night when all the batteries happen to conk out on us. In a multiplayer game it can make the difference between you being the tea bagger or getting tea bagged.
When I purchased my kit the bundle was less expensive than buying all the parts separately (wireless controller, play and charge cable, and rechargeable battery). The kit shipped without any problems and everything worked when it arrived. They come in so handy that we got four of them, so we can connect all our controllers and play.
Personally I am a big fan of using original manufacturer parts from the console maker over third party manufactured controllers. The Xbox play and charge controllers were well thought out and just make economic sense.
Now really, why whould you want to buy anything else...
Everything you need for continuous gaming is here in one package. The Wireless Controller gets you into the game
without being tied down, while the play and charge kit lets you charge up while you play and gives you up to 35 hours of play with every charge.