Utility
The Chevrolet and the Mazda MAZDA6 can accommodate the same number of passengers.
Dimensions
The Mazda MAZDA6 is tremendously heavier than the Chevrolet.
Your wallet will hurt more every time you fill up the MAZDA6 than the Chevrolet Cobalt because of its bigger tank.
The Chevrolet Cobalt and the Mazda compete for the same parking spaces.
The MAZDA6's longer wheelbase will result in a smoother, more stable ride; on the other hand, the Chevrolet Cobalt may give a nimbler feel in daily traffic.
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 Cobalt to the dealership as the Mazda MAZDA6.
The MAZDA6 is tremendously more expensive than the Chevrolet in terms of MSRP.
Handling
With their similar turning circles, the Chevrolet Cobalt and the Mazda MAZDA6 most definitely handle roughly the same into and out of tight spots.
Drivetrain
The MAZDA6's engine isn't much bigger than the Chevrolet's.
The Cobalt could learn a lesson or two from the Mazda MAZDA6 regarding torque.
Comfort
While the front cabin in the MAZDA6 offers a bit more head room than the Chevrolet Cobalt, there really isn't much of a difference.
The ampler interior dimensions of the Mazda make it roomier for your passengers than the Chevrolet Cobalt.
Warranty
The Mazda MAZDA6 and the Chevrolet have the same basic after-sale protection.