My lease just ended on November 1st on my CLK55. It was a black on black cabriolet. I LOVED the car. I had a porsche 993 series carrera before that and liked it even more. It was fast, the top went down smoothly with very little effort. I had few problems with it.
BUT... I have a new girlfriend now....I have a nero on black GS. Leather inserts and carbon fiber trim everywhere you could put it. I use it as a daily driver and every night I am excited to know that I can wake up and drive this car. I have had the car 2 months and put on 1200 miles. There are so many things about the GS that I love:
-I have never seen another GS on the road in the U.S.
-It is very loud, and the sound is italian and fantastic
-It is very fast. faster than the clk55
-it handles very well, much better than the clk55.
In many ways the GS is similar to the CLK55. V-8, front engine, 2+2 seating, and similar dimensions. If you have never owned an exotic car, it is not at all like owning a mass produced car.
Good luck.