I purchased this car used in January of 2012 with 480k miles. Now, before you think I'm crazy, my reasoning was that after I test driving the car, it appeared to be mechanically sound in every way. The engine was as quiet as if it had 60k miles and the transmission shifted to perfection. Being a long time lover of Lexus, I can now appreciate the maintenance-free GS300. Since purchasing the car, I've replaced the water pump and the pulley, along with the brakes and rotors all around. So far my air suspension has been fine, although I suspect the ball joints will need replacing soon. Despite that, I'm very happy with the car. It's a joy to drive and gets a lot of attention.
Powerful 5.0L V8 engine. Very smooth and agile for its size. The timeless look of this vehicle can fool most people as to it's actual age. Also, the many MB forums on the web are great and full of very helpful information that any MB could ever need.
Putting air suspension into this vehicle was a horrible idea. Mercedes could also have done a better job with the electronics in this car. I didn't pay MSRP for this car, but I couldn't imagine buying this car brand new and dealing with the issues that I've read about so far.