Since its inception about a decade ago, the large luxury SUV segment has been dominated by vehicles from American and Japanese automakers. This year, however, Mercedes-Benz is joining the world of the big and the bold with its all-new GL-Class, whose arrival ushers in a new level of luxury and performance.

Mercedes once planned on having the GL-Class replace the comparatively ancient and crude G-Class (a.k.a. Gelaendewagen) but has since decided it will continue to produce the smaller, military-themed vehicle in small numbers. The G and GL are not related. Instead, the 2007 Mercedes-Benz GL-Class is built alongside the midsize M-Class SUV and R-Class wagon in Mercedes' Tuscaloosa, Alabama, factory.

The GL's big advantage over the M is its extra length behind the rear seats. It's about as long as a Cadillac Escalade, but with a longer wheelbase and a narrower width. Unusual for this class of vehicle, the GL is built on a carlike unibody architecture. Most competitors feature a truck-based body-on-frame design. Also unusual is the GL's engine lineup. In addition to a powerful gasoline V8, which you'll find in the GL450 model, Mercedes is offering a turbodiesel V6 in the GL320 CDI. The diesel GL gives up some quickness but offers gas mileage in the 20s. Unfortunately, it's only 45-state certified, meaning you won't be able to buy it in California, New York, Maine, Massachusetts or Vermont.

Everywhere you look it's apparent Mercedes has done its research for what's expected in this segment. Both the GL450 and GL320 CDI have seating for up to seven passengers, a roomy cargo hold, capable off-road performance and the ability to tow the usual upscale lifestyle accessories. Standard equipment highlights include a seven-speed automatic transmission, an adjustable air suspension, powered and heated front seats and a full complement of airbags. Many advanced luxury items are also available, such as surround-sound audio and adaptive cruise control.

Though full-size trucks and SUVs aren't exactly in vogue right now, that shouldn't diminish what Mercedes has accomplished here. In its first year, the 2007 Mercedes-Benz GL-Class is already a very viable choice in the luxury SUV segment, which includes the likes of the Audi Q7, Escalade, Infiniti QX56 and Lincoln Navigator. If you're in the market for such a vehicle, you'll definitely want to check out the three-pointed star's new SUV.

The 2007 Mercedes-Benz GL-Class is a large luxury SUV, and Mercedes sells it in GL320 CDI and GL450 versions. Included as standard on both models are 18-inch alloy wheels, a load-leveling air suspension, rain-sensing wipers, electric closing assist for the rear tailgate, dual-zone automatic climate control, power and heated front seats, wood interior trim, the COMAND interface and a power-folding third-row seat. The audio system has a glovebox-mounted six-disc CD/MP3 changer and an auxiliary input jack. A GL450 equipped with the optional Premium Package also comes with a navigation system, memorized driver-seat positioning, park assist, a surround-sound Harman Kardon audio system, satellite radio and a power-operated tailgate.

Other options include 19-inch wheels, a sunroof, xenon HID headlights with adaptive lighting, adaptive cruise control, full leather upholstery, tri-zone climate control, Keyless Go, a Class IV trailer hitch, a rear-seat entertainment system, a dedicated iPod integration kit and upgraded front seats. The GL450 can also be equipped with the Off-Road Package that features skid plates, adaptive damping, a two-speed transfer case and two locking differentials.

Each GL-Class SUV has its own engine. The GL320 CDI comes with a 3.0-liter turbodiesel V6 equipped with direct injection and a particulate filter. It's rated for 215 hp and 398 pound-feet of torque. Under the hood of the GL450 is a 4.7-liter gasoline V8 capable of 335 hp and 339 lb-ft of torque. A seven-speed automatic transmission with manual shift control is standard on both models. All GLs come with an all-wheel-drive system that requires no driver intervention; GL450 buyers planning to do regular off-roading should opt for the more advanced, dual-range 4WD system in the Off Road Package (not available on the GL320). The GL450 is very quick for a large SUV, as it can sprint to 60 mph in just 6.7 seconds. Fuel mileage is rated at 15 city, 19 highway. The GL320 CDI is not as fast, but offers adequate acceleration along with an impressive 20/25 EPA rating. Properly equipped, any GL-Class SUV can tow 7,500 pounds.

Standard safety features on the 2007 Mercedes-Benz GL320 CDI and GL450 include stability control, antilock brakes with brake assist, whiplash-reducing front headrests, first- and second-row side airbags and full-length side curtain airbags with an integrated rollover sensor. Hill start assist, hill-descent control and Tele Aid are also included. Buyers wanting front and rear parking sensors should note that they are only available as part of the Premium Package.

Despite its small 4.7-liter V8, the Mercedes-Benz GL450 is the muscle car of its class. It is quicker to 60 mph than any other large SUV we've tested, including the Cadillac Escalade and Audi Q7. It's also quiet on the highway, with minimal wind and road noise. Although the diesel GL isn't going to break any acceleration records, passing and merging maneuvers come easily, as the seven-speed automatic transmission does an exemplary job of keeping the engine in the meat of its power band. In addition, the GL320's V6 is so quiet and refined you're scarcely aware it's actually a diesel.

Some drivers might find the Mercedes GL's handling to be a bit wallowy -- this isn't a truck you toss around for the sheer joy of it. But the ride and handling compromise is acceptable, and the GL's steering, although a bit slow, is nicely weighted and never numb.

The GL's cabin is well-appointed and a comfortable place to be. Fit and finish is as it should be, seat comfort is exceptional, and headroom and legroom are ample for all positions. Nice touches include a one-touch up and down function for all four windows and flush-folding rear headrests to improve the driver's rearward vision. Third-row access is also well thought out. With the second- and third-row seats lowered, 83 cubic feet of cargo volume is available.