Utility
Neither the H2 SUV nor the Mercedes-Benz GL-Class has a marked advantage as far as seating capacity.
The HUMMER H2 SUV is likely a better choice than the Mercedes-Benz GL-Class with respect to transporting cargo, especially if you often need to carry a lot of stuff or big pets.
Performance
With that kind of horsepower, both the HUMMER and the Mercedes-Benz GL-Class are legitimate sportscars.
Dimensions
The HUMMER H2 SUV is significantly more bulky than the GL-Class.
Your wallet will hurt more every time you fill up the HUMMER H2 SUV than the Mercedes-Benz GL-Class because of its bigger tank.
The HUMMER H2 SUV and the Mercedes-Benz 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 about the same to get the Mercedes-Benz GL-Class to the dealership as the HUMMER H2 SUV.
With respect to MSRP, the Mercedes-Benz GL-Class doesn't cost much less than the HUMMER H2 SUV.
Handling
With its tighter turning radius, the GL-Class is most certainly sprier than the HUMMER H2 SUV, something to consider if you do a lot of city driving; however, keep in mind that a vehicle with a tight turning circle may feel a bit twitchy on the highway.
Drivetrain
The HUMMER H2 SUV has a bigger engine than the GL-Class. Keep in mind that smaller engines typically get better gas mileage, but smaller engines can be stressed more.
The Mercedes-Benz GL-Class could learn a lesson or two from the HUMMER as far as torque.
Torque equals pickup, and the HUMMER H2 SUV will have picked up and gone by the time the Mercedes-Benz finally gets moving.
Comfort
While the front cabin in the H2 SUV offers a bit more head room than the Mercedes-Benz GL-Class, there honestly isn't much of a difference.
The Mercedes-Benz GL-Class is not particularly roomier for your passengers than the HUMMER H2 SUV.
Warranty
The Mercedes-Benz GL-Class and the HUMMER H2 SUV have the same basic warranty.