I would never buy a Toyota.
They are good cars, but just plain boring.
Mercedes AMG series are usually still boring with too smooth/quiet rides, but the C63 and SLK55 are the most fun MB's to drive.
Depends...Mercedes are good if you get top of the line. Otherwise, you are only paying for the label. There really isn't anything special about them. For that money, you could get a very nice car (infiniti, acura, etc.) If you have the money, I'd definitely get a benz. Otherwise, go with the toyota. They hold their value better anyways.