Handling
With their similar turning radii, the Mazda MAZDA3 and the Honda most definitely handle about the same into and out of tight spots.
Drivetrain
The Honda's engine is slightly smaller than the Mazda's, but not terribly so.
The Honda Civic has no lessons to learn when it comes to torque from the Mazda MAZDA3.
Utility
Neither the Mazda MAZDA3 nor the Honda Civic has a marked advantage when it comes to seating capacity.
Convenience
You'll most definitely take the Honda Civic for a fill-up almost as often as the Mazda MAZDA3.
Comfort
While the front cabin in the Honda Civic offers a bit more head room than the MAZDA3, there frankly isn't much of a difference.
The Mazda MAZDA3 is not particularly roomier for your passengers than the Honda Civic.
Dimensions
Your wallet will hurt more every time you fill up the Mazda MAZDA3 than the Honda Civic because of its bigger tank.
The Honda Civic and the Mazda MAZDA3 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 Honda Civic to the dealership as the MAZDA3.
The MAZDA3 requires a lot of gas compared to the Honda.
With respect to fuel economy, the Honda Civic beats the Mazda MAZDA3.
The Honda Civic isn't much costlier than the Mazda MAZDA3 as far as MSRP.
Warranty
The Honda Civic and the Mazda MAZDA3 have the same basic after-sale protection.