Drivetrain
The Subaru Tribeca's engine is a tad smaller than the CX-9's, but not terribly so.
The Subaru Tribeca has no lessons to learn as far as torque from the Mazda CX-9.
Utility
The CX-9 and the Subaru can accommodate the same number of passengers.
Convenience
You will most certainly have to visit your friendly gas station more often with the Subaru Tribeca than with the Mazda CX-9.
Comfort
While the front cabin in the CX-9 offers a bit more head room than the Subaru, there really isn't much of a difference.
The Mazda provides more head- and leg-room to your passengers than the Tribeca does.
Dimensions
Your wallet will hurt more every time you fill up the Mazda CX-9 than the Subaru Tribeca because of its larger tank.
The Subaru Tribeca and the Mazda CX-9 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 approximately the same to get the Subaru Tribeca to the dealership as the CX-9.
Producing an exact gas mileage evaluation is so hard that some think not even the federal government can do it, but it looks as though both the Tribeca and the Tribeca perform about similarly with respect to fuel economy.
There really isn't much of a difference in gas mileage here, but if you must know, the Mazda CX-9 is a tad more economical than the Subaru Tribeca.
The Subaru Tribeca isn't much less costly than the Mazda in terms of MSRP.
Warranty
The Subaru Tribeca and the Mazda CX-9 have the same basic warranty.