The New York Time has a great piece about the AMG onslaught from Mercedes and what makes the so unique and popular. This particular quote sums up the entire article, but I suggest you read it because this is certainly a unique perspective at the AMG models.

the CLS has a way of turning even everyday streets into your own personal racetrack.

What amazes me the most is the ability for AMG to produce 20k engine every year by hand. That is craftsmanship.