2009 Mercedes-Benz GL-Class

All GL-Class models ride on a four-wheel independent air suspension that provides a comfortable, quiet ride. Several reviews say the large and heavy Mercedes-Benz GL is not well suited for aggressive driving because the suspension is too soft. Cars.com's Kelsey Mays questioned the value of the optional Adaptive Damping System, noting the Sport mode transmits "a good deal of expansion joint harshness into the seat bottom," while the Comfort mode feels "floaty and vague." He adds, "The GL isn't an athletic vehicle in any mode," but the suspension's default mode is "more than sufficient for most situations." Other reviews say the GL handles exceptionally well for a large SUV.

The seven-passenger Mercedes  GL-Class has three rows of seats as standard equipment, and reviewers like the way the second row slides forward on the right side for easy access to the roomy third row. Cargo space behind the third row is only 14 cubic feet, but a standard power-folding feature expands the space to 44 cubic feet. Folding the second row reveals a maximum of 83.3 cubic feet, notably smaller than most other large SUVs.

Three engine choices define three models

Three models are identified by their powertrain: a 335-horsepower, 4.6-liter V-8 powers the GL450, while the higher performance GL550 is powered by a 5.5-liter V-8 rated at 382 horsepower. New for 2009 is the GL320 Bluetec, with a low-emissions, 3.0-liter, turbodiesel V-6 rated at 210 horsepower. The diesel's emissions are kept low by the injection of AdBlue, a urea-based solution, into the exhaust stream. The diesel engine is remarkably fuel efficient, with Environmental Protection Agency ratings of 17 mpg city and 23 mpg highway. All engines benefit from an efficient seven-speed automatic transmission, but both of the gas engines are considerably thirstier: 13 mpg city and 17 mpg highway for the GL550, and 13 city and 18 highway for the GL450.

The GL320 Bluetec's diesel V-6 engine produces an impressive 391 pound-feet of torque, more than either of the gas V-8s. Testers say the diesel is smooth, quiet and responsive, except from a standstill. ConsumerGuide.com explains: "The 320 Bluetec can feel slightly lethargic off the line," but they add that it "never feels underpowered." The V-8 engines "deliver effortless thrust," editors say. Not every gas station sells diesel, so you may want to consider that if the GL Bluetec is on your list. Still, as alternatives to gasoline go, diesel is much more readily available than E85 ethanol.

Edmunds.com points out that several competitors like the Cadillac Escalade (*Est. $62,205 to $87,435) and Lincoln Navigator (*Est. $53,120 to $59,020) have greater cargo capacity, "but they can't match the GL's polish and on-road handling." Several reviews point out the midsize Audi Q7 (*Est. $43,500 to $59,220) or the five-passenger Mercedes M-Class (*Est. $44,600 to $90,100) are worthy alternatives to the GL if interior room and towing capacity are not as important.

The best review comes from Cars.com, with a comprehensive evaluation and plenty of driving impressions. NewCarTestDrive.com provides a detailed test-drive report with extra information on the three models and available equipment. CNET gives a good description of the cabin technology along with a behind-the-wheel report. Well-written, informative road-test evaluations can also be found at ConsumerReports.org, Edmunds.com, ConsumerGuide.com and TheCarConnection.com.