Handling
With its tighter turning circle, the Toyota Sienna is definitely more maneuverable than the Quest, something to consider if you do a lot of city driving; however, bear in mind that a vehicle with a tight turning circle may feel a bit twitchy on the highway.
Drivetrain
The Nissan Quest has no lessons to learn in terms of torque from the Toyota Sienna.
Utility
Neither the Nissan nor the Sienna has a marked advantage when it comes to seating capacity.
The Toyota Sienna is a better choice than the Nissan Quest regarding transporting cargo, especially if you often need to carry a lot of luggage or sizeable animals.
Comfort
While the front cabin in the Toyota Sienna offers a bit more head room than the Nissan, there honestly isn't much of a difference.
The Nissan Quest offers more head- and leg-room to your passengers than the Toyota Sienna does.
Dimensions
The Toyota Sienna and the Nissan Quest compete for the same parking spaces.
Cost
The Nissan Quest won't tax your gas budget substantially more than the Toyota Sienna will.
The Toyota Sienna doesn't pale in comparison to the Nissan as far as gas mileage.
The Quest isn't much more expensive than the Toyota Sienna regarding MSRP.
Warranty
The Toyota and the Nissan Quest have the same basic after-sale protection.