Handling
With their similar turning circles, the E-Class and the Audi A6 likely handle roughly the same into and out of tight spots.
Drivetrain
The Audi's engine is a bit smaller than the Mercedes-Benz E-Class's, but not terribly so.
The Audi A6 has no lessons to learn when it comes to pickup from the Mercedes-Benz E-Class.
Utility
The Mercedes-Benz E-Class's more massive trunk will accommodate more large things than the Audi.
Drivers with frequent child-duty might favor the E-Class over the Audi A6.
Convenience
You most definitely won't have to visit your friendly gas station more often with the Mercedes-Benz E-Class than with the Audi, because both offer similar mileage ranges.
Comfort
Taller drivers will markedly enjoy the extra head room in the Mercedes-Benz E-Class's front cabin compared to the Audi.
While the rear of the Mercedes-Benz E-Class offers a bit more head- and leg-room than the A6, there honestly isn't much of a difference.
Dimensions
The Mercedes-Benz is a little more ponderous than the Audi.
The Mercedes-Benz and the Audi A6 compete for the same parking spaces.
Cost
The destination charge is a standard charge for transporting the vehicle from its point of origin to the dealer. It costs roughly the same to get the Audi A6 to the dealership as the Mercedes-Benz E-Class.
The Mercedes-Benz E-Class won't tax your gasoline budget markedly more than the Audi A6 will.
The Audi is substantially less costly than the Mercedes-Benz E-Class in terms of MSRP.
Overview
The E-Class and the Audi have the same basic warranty.