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 Toyota Highlander to the dealership as the Mercury.
The Mercury Mountaineer consumes a lot of gasoline compared to the Highlander.
The Toyota will save you money at the pump compared to the Mercury Mountaineer.
As far as MSRP, the Mercury costs roughly as much as the Toyota Highlander (though the Toyota Highlander is a tad cheaper).
Utility
Neither the Toyota Highlander nor the Mercury Mountaineer has a marked advantage when it comes to seating capacity.
The Mercury Mountaineer outpulls the Highlander by a sizeable margin.
Convenience
The Toyota Highlander's fuel tank will need to be replenished a bit more often than the unit in the Mercury.
Comfort
While the front cabin in the Toyota Highlander offers a bit more head room than the Mercury Mountaineer, there frankly isn't much of a difference.
The ampler interior dimensions of the Toyota Highlander make it significantly more spacious for your passengers than the Mercury Mountaineer.
Dimensions
The Mountaineer is significantly more bulky than the Highlander.
Your wallet will hurt more every time you fill up the Mercury Mountaineer than the Toyota Highlander because of its larger tank.
The Toyota Highlander and the Mountaineer compete for the same parking spaces.
Handling
With their similar turning circles, the Mercury Mountaineer and the Toyota definitely handle roughly the same into and out of tight spots.
Drivetrain
The Toyota Highlander's engine is considerably smaller than the Mercury Mountaineer's. Keep in mind that a smaller engine usually has to work a little harder; however, smaller engines typically get better gas mileage.
Torque is the force that lets you accelerate quickly, and in this respect, the Mercury Mountaineer isn't much more powerful than the Toyota.
Overview
The Mercury Mountaineer and the Toyota Highlander have the same basic after-sale protection.