Utility
The Mercedes-Benz GL-Class will quite certainly prove friendlier than the HUMMER for those of you with frequent kid-cargo.
The HUMMER H2 SUT is likely a better choice than the GL-Class with respect to transporting cargo, especially if you frequently need to carry a lot of equipment or large pets.
There's little the HUMMER H2 SUT can tow that the GL-Class cannot.
Dimensions
The HUMMER H2 SUT is considerably heavier than the Mercedes-Benz GL-Class.
Your wallet will hurt more every time you fill up the HUMMER than the Mercedes-Benz GL-Class because of its bigger tank.
The H2 SUT and the GL-Class 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 almost the same to get the Mercedes-Benz to the dealership as the HUMMER H2 SUT.
As far as MSRP, the GL-Class doesn't cost much less than the HUMMER H2 SUT.
Handling
With its tighter turning circle, the Mercedes-Benz GL-Class is most certainly more maneuverable than the H2 SUT, something to consider if you do a lot of city driving; on the flip side, note that a vehicle with a tight turning circle may feel a bit twitchy on the highway.
Drivetrain
The HUMMER's engine is significantly larger than the Mercedes-Benz GL-Class's. Bear in mind that more sizeable engines may use more gasoline than smaller ones.
The Mercedes-Benz GL-Class could learn a lesson or two from the HUMMER H2 SUT in terms of pickup.
Torque equals pickup, and the HUMMER H2 SUT will have picked up and gone by the time the Mercedes-Benz GL-Class finally gets moving.
Comfort
While the front cabin in the HUMMER H2 SUT offers a bit more head room than the Mercedes-Benz, there honestly isn't much of a difference.
The Mercedes-Benz GL-Class is not particularly more spacious for your passengers than the HUMMER H2 SUT.
Warranty
The Mercedes-Benz GL-Class and the HUMMER H2 SUT have the same basic after-sale protection.