 I traded a 2008 E350 Sport for a 2012 E350 Sport primarily to get the more fuel efficient engine and an updated Command System.The Command System is a huge improvement; but I have been somewhat disappointed in the fuel efficiency.The EPA projected a 25% improvement (16/24 vs 20/30), but I have seen just a 10% improvement. Mind you, 19/29 in normal driving is not to be laughed at, but not what I expected.On a 1700 mile road trip which included several hundred miles of mountain driving, I did average 31.7 mpg.I would say that this car is more comfortable than the 2008.This is my fourth E Class and they just keep getting better.I have now owned this car for 3 years and logged 32,000 miles.  It is without a doubt the best car I have ever owned.  Normally after 3 years I would be looking for another car, but no matter what I drive, it just doesn't measure up to this car.  I have maintained it "by the book", and the only surprise I have had is that I had to replace the motor mounts at 50,000 miles and this was covered by my CPO warranty.  My favorite "creature features" are Keyless-Go and Bluetooth phone and audio.  On my morning commute, I have to merge into heavy high speed traffic.  This car has plenty of smooth power.  I should change the title of this review to THE BEST.