Not sure if it's been said yet but i think the controller is really designed well and that shows by how it has stood the test of time, especially considering it is an electronic device which we all know is notorious for being outdated almost as soon as it is released.
I feel there is one major advantage of the x360 controller over the dualshock however, and that is the location of the left analogue stick, it works much better being up higher where the dpad on the dualshock is. It is more comfortable in your hands and i find this provides a better experience, most notably on fps games.