I am a new MB owner and am glad to have made the switch. I purchased my used 4matic this year and have been pleased with the performance thus far. My only dislikes would be the automatic wiper sensors when it rains and comfort mode. I highly recommend Sport mode to really know what your driving. I also think the windows should be a shade darker.
Sport mode and automatic rear shade (I have young children and helps keep the sun out of their eyes and the car cool in the summer)
Memory seats a must for this style car, better sensors on the automatic blades, cheaper oil changes.