For 2010, Yukon XL gets upgraded with OnStar 8.2, USB input, E85 capability on all 5.3-liter engines, and the single-speed all-wheel-drive system. The 6.2-liter engine adds active fuel management that shuts off some cylinders in low-load driving, and Denali gets a taller axle ratio for better highway mileage. The Yukon XL was completely redesigned for 2007. 

The Yukon XL is a great choice for anyone towing cars, boats, horses, and travel trailers with an SUV. Maximum towing capacity is 8100 pounds for a Yukon XL 1500 model, or 9600 pounds on a Yukon XL 2500; subtract 2500 pounds if the Yukon is fully loaded with people and cargo. With its long wheelbase and heavy-duty construction, the Yukon XL is a stable platform for towing while offering the interior cargo advantages of a full-size SUV. 

Like Suburban, Yukon XL is offered in half-ton or three-quarter ton capacities. Yukon XL is also available as a luxurious Denali model that compares well to Cadillac's Escalade ESV. Denali comes equipped with automatic rear load-leveling. 

Inside is a comfortable cabin. We found the Yukon XL's optional leather seats comfortable. The driver sits way up high for a commanding view of the road, and the pedals power-adjust to fit short and tall drivers. The instruments and gauges are best in class, elegantly clean yet very functional. Interior small items storage is intelligently designed and all over, including a huge center console. 

Second-row passengers will find a lot of leg room in the Yukon XL. Heated bucket seats with a center console between them are available for the second row, turning them into first-class accommodations; and there is a power folding option, making it easier for third-row passengers to climb by. There's even decent legroom and good headroom in the third row. 

Yukon offers a choice of engines. GM's trusty 5.3-liter Vortec V8 is the standard choice and it's a good one, making 320 horsepower and 335 pound-feet of torque. We enjoyed its smooth power. The 5.3-liter gets an EPA-estimated 15/21 miles per gallon City/Highway. Flex-fuel versions of the 5.3-liter V8 are available that can run on E85 ethanol, though use of less-efficient ethanol drops fuel economy to an EPA-estimated 11/16 mpg City/Highway. 

A 6.2-liter V8 with variable valve timing, delivering 395 horsepower and 417 pound-feet of torque is optional for Yukon XL 1500-series models. A superb engine for towing, the big, powerful 6.2-liter is EPA-rated at 12/19 mpg. 

At the top of the Yukon XL line is the Denali, a luxury model with a 403-hp V8. The Denali is offered with two-wheel drive or all-wheel drive, the latter an excellent aid for inclement weather but not designed for serious off-road use. The Denali comes standard with the AutoRide active electronic suspension, which is optional on the regular Yukon XL. The Denali models come with a 6.2-liter V8 that produces 403 horsepower and 417 pound-feet of torque and gets an EPA-rated 13/20 mpg with all-wheel drive. 

For 2010, Yukon XL is available with all-wheel drive (also on Denali), or a four-wheel drive system with low range with a full-time position that can be used on dry pavement. Yukon XL is also available with 2WD. All Yukon XL and Denali models use a six-speed automatic transmission. They all have a Tow/Haul mode that reduces upshifting and downshifting, and also shifts quicker, so the transmission doesn't work so hard when pulling a big load. Transmission oil temperature is part of the instrumentation. 

Convenience features include a power rear liftgate, a 14-speaker Bose sound system, a navigation system, and a DVD rear-seat entertainment system. Rearview cameras are standard with navigation and available for others with display in inside mirror. 

Yukon XL competes with the Ford Expedition EL, Chevy Suburban, and, if cargo space isn't as important as tow rating, the Toyota Sequoia. Yukon XL Denali alternatives include the Lincoln Navigator L, Cadillac Escalade ESV, and Mercedes-Benz GL450. 

Virtually ever major mechanical component, including the engine, transmission, axles, suspension, steering, brakes, wheels and tires is different on the 2500-series Yukon XL. Yukon XL 2500 models come with a 352-hp 6.0-liter V8 with 382 pound-feet of torque, a six-speed automatic, and rear-wheel drive or four-wheel drive.