Cost
The Suzuki will save you money at the pump compared to the Kia Sorento.
Regarding fuel economy, the Suzuki is slightly better than the Sorento, but not by much.
Regarding MSRP, the Kia Sorento costs almost as much as the Suzuki Grand Vitara (though the Suzuki Grand Vitara is a bit cheaper).
Utility
The Suzuki Grand Vitara and the Kia Sorento can accommodate the same number of passengers.
Towing is considerably more the Kia Sorento's forte than it is the Grand Vitara's.
Convenience
You'll definitely take the Suzuki Grand Vitara for a fill-up roughly as often as the Kia Sorento.
Comfort
While the front cabin in the Suzuki Grand Vitara offers a bit more head room than the Kia Sorento, there honestly isn't much of a difference.
While the rear of the Kia Sorento offers a bit more head- and leg-room than the Suzuki Grand Vitara, there honestly isn't much of a difference.
Dimensions
The Kia Sorento is significantly more bulky than the Suzuki Grand Vitara.
Your wallet will hurt more every time you fill up the Kia than the Suzuki Grand Vitara because of its larger tank.
The Suzuki Grand Vitara and the Kia Sorento compete for the same parking spaces.
Performance
As far as horsepower, the Kia packs quite a wallop and will knock the Suzuki down a few rungs. However, remember that high horsepower engines often command higher insurance premiums.
Handling
With their comparable turning circles, the Kia and the Suzuki Grand Vitara most definitely handle roughly the same into and out of tight spots.
Drivetrain
The Sorento's engine is substantially bigger than the Suzuki's. Bear in mind that bigger engines may use more gasoline than smaller ones.
The Suzuki Grand Vitara could learn a lesson or two from the Kia Sorento as far as torque.
Warranty
The basic warranty that comes with the Grand Vitara isn't quite as generous as the Kia's.