Performance
In terms of horsepower, the GMC Sierra 2500HD packs quite a punch and will knock the Toyota Tacoma down a few rungs. However, bear in mind that high horsepower engines often command higher insurance premiums.
Handling
With its tighter turning circle, the Tacoma is most certainly more maneuverable than the GMC Sierra 2500HD, something to consider if you do a lot of city driving; on the flip side, keep in mind that a vehicle with a tight turning circle may feel a bit twitchy on the highway.
Drivetrain
The Sierra 2500HD's engine is tremendously more sizeable than the Toyota Tacoma's. Keep in mind that more massive engines may use more gas than smaller ones.
Torque equals pickup, and the GMC Sierra 2500HD will have picked up and gone by the time the Toyota Tacoma finally gets moving.
The GMC Sierra 2500HD packs quite a punch compared to the Toyota Tacoma regarding torque, which is roughly equivalent to acceleration.
Utility
The GMC Sierra 2500HD will quite certainly prove friendlier than the Toyota Tacoma for those of you with frequent child-cargo.
The GMC Sierra 2500HD is a better choice than the Toyota Tacoma in terms of transporting cargo, especially if you often need to carry a lot of suitcases or massive animals.
Towing is considerably more the GMC's forte than it is the Toyota Tacoma's.
Comfort
Taller drivers will substantially enjoy the extra head room in the GMC Sierra 2500HD's front cabin compared to the Toyota Tacoma.
The ampler interior dimensions of the Sierra 2500HD make it more spacious for your passengers than the Toyota Tacoma.
Dimensions
The GMC is tremendously heavier than the Toyota Tacoma.
Your wallet will hurt more every time you fill up the GMC Sierra 2500HD than the Toyota Tacoma because of its bigger tank.
The Toyota Tacoma fits in smaller parking spaces than the GMC.
The GMC Sierra 2500HD's longer wheelbase will likely result in a smoother, more stable ride; on the flip side, the Toyota Tacoma may give a more maneuverable feel in daily traffic.
Cost
The destination charge is a standard charge for transporting the vehicle from its point of origin to the dealer. The Toyota Tacoma is significantly cheaper to get to the dealership than the GMC Sierra 2500HD.
The GMC Sierra 2500HD is tremendously pricier than the Toyota regarding MSRP.
Warranty
The GMC and the Toyota Tacoma have the same basic after-sale protection.