Free scheduled maintenence.
 

Mercedes-Benz was the first to have free scheduled maintenence under the initial warranty period of 50,000 miles. They stopped it for 2005 and I can tell you that it's one of the greatest features of the car.

Bring it in, drop it off, they go over the thing from top to bottom. They really go out of their way to take care of their customers but as of this current model year it's gone. Shame. Last time in there they replaced a ton of things that I didn't even know needed to be replaced.

The ML 500 and the CLS 500 are really hot. However, an upgrade isn't as exciting without that free scheduled maintenance.