The best controller I have ever used. It is so comfortable, and Im sure it will not get tiring with extended game sessions.
I've been using this to play Halo 2 on the PC, and whilst Im still getting used to aiming with the joysticks, I am improving.
All too often with other gamepads, you feel overwhelmed with the buttons, if they are even mapped properly. Every button is mapped in Halo 2 intuitively, and if more games follow suit, and use the vibration capabilities well, the controller may begin to play a key part in PC gaming that is all too dominated by the mouse and keyboard combo.
The vibration feedback is a little strong however, and whilst feeling good when felt in short bursts. When "spraying" fire, the unit shakes along with its buttons (especially the xbox guide button) which makes a rattly noise.
Additionally the joystick buttons make a loud sound when pressed. Like somebody cracking their knuckles loudly.
All of this does not detract from the experience however. If you have a Windows Vista Machine, and need a gamepad, you can't do better than this attempt by Microsoft to unify controller gaming for the PC Platform. Just plug it into a USB port, and the drivers are automatically downloaded and installed by Windows Update. No configuration or calibration neccessary.