GM's trusty 5.3-liter Vortec V8 is the standard choice and it's a good one, making 310 horsepower and 335 pound-feet of torque with 4WD and 320 hp and 340 pound-feet of torque with 2WD. GM's Vortec is one of the best V8s around, though Chrysler's 5.7-liter Hemi V8 and Toyota's new 5.7-liter V8 are also quite impressive. When you floor it, it actually feels like it has more horsepower than advertised, considering the weight of our test vehicle was 5758 pounds.

There's a smooth four-speed automatic transmission to go with it, and with all that torque, a fifth speed in the transmission might not be needed, though the big Japanese V8 SUVs all have five- or six-speed automatic transmissions. In the Yukon XL, the 5.3-liter V8 is FlexFuel capable, meaning the engine can run on either unleaded regular fuel or E85 (85 percent ethanol and 15 percent gasoline).

If you need more power for towing, get the optional 366-hp 6.0-liter V8, which boasts 380 pound-feet of torque, handy for getting up Southern California's Grapevine and other steep grades.

If you have a seriously heavy trailer you can choose one of the 2500 series models, which have a 352-hp 6.0-liter V8 with 383 pound-feet of torque.

You can also opt for the Denali XL, with its Corvette-based 6.2-liter engine making 380 hp and 417 pound-feet of stump-pulling twist.

Active Fuel Management is standard on the 5.3-liter V8 and the 6.0-liter V8 in 1500 models. AFM shuts down four of the eight cylinders when they're not needed to save fuel. But there's one big catch: all the cylinders are needed virtually all time, unless you're totally off the throttle, in which case they all basically shut down anyhow. So the amount of fuel saved is questionable.

Fuel economy with the 5.3 V8 and 2WD is an EPA City/Highway-rated 14/20 miles per gallon. We drove nearly 300 miles in a 2WD Yukon XL in an even split between around town and running 75 mph on the freeway, and averaged 15.8 mpg. With the 6.0-liter V8, the EPA ratings are lower at 12/17 City/Highway. (Better is the Yukon Hybrid's 21/22 mpg.)

Ride quality in the Yukon XL is excellent, overall. Even when the optional 20-inch wheels are chosen, the suspension deals deftly with road imperfections and potholes. We prefer taller tires on our trucks, however. The Yukon XL is very stable, though it wallows a bit on undulating freeways.

The rack-and-pinion steering feels fairly direct, though as in other big SUVs it is a bit slow. Also like all large SUVs, the Yukon XL is prone to body lean in turns and doesn't respond well to quick changes of direction. It's a full-size truck and needs to be driven accordingly and with respect for others, not like it's a sports car.

AutoRide, the optional self-leveling suspension, is a high-tech, active suspension, meaning it electronically adjusts to the road, as read by sensors. It reduces some of that body lean in corners, as well as nose dive under hard braking.

Hard winds can blow it around. Driving in an 25-mph crosswind on the freeway at 75 miles per hour, our Yukon XL swayed all over the road, because of its billboard-like profile. So if you're pulling a 20-foot enclosed trailer, you'll want to slow down in heavy wind.

The brakes feature big vented rotors, 13 inches up front and 13.5 inches in the rear. This adds up to security and safety when you're trying to get stopped with a boat or trailer pushing you from behind. The brakes on these GM trucks are far better than they were a decade or so ago if you have memory of those.