I own an AMG and its great! I have a slightly older `99 model and for me its the ultimate wolf in sheeps clothing, a lot of the new models have a lot of bling and for me its too much show, fast mercs where always about being understated, they would rip most cars but not shout about it. A lot of people say my black E55 looks like a taxi, they are right, it looks like every other 95-02 E class but thats whats great about it.
People will always compare the E55 to the M5 when they shouldnt, they are the same size/weight/performance but not the same car, I always hear "why didnt you get an M5, they are much more sporty" true, but when a car weighs in at nearly 2 tons and has that much luxury and ergonomics it will never be a sports car, the M5/E55 where always designed to be long distance cruisers at high speed, the merc is simply better at it. if you want sporty, get something lighter. if yu want to drive to Austria and feel like you have driven to the local shops get the merc, (ignore the £1200 in fuel to get there and back, and yes it was worth it,)