We've driven three versions of the 2007 GMC Sierra near Scottsdale, Arizona. We found all of them to be comfortable. The 5.3-liter V8 provided plenty of power for the extended cab SLE models we drove and the 6.0-liter V8 was more than enough for the SLT Crew Cab.

Of the suspensions, the Z83 offers the smoothest ride while the Z85 is slightly stiffer and for those who often tow trailers. The Z71 is set up to enhance off-pavement driving. The Z60 configuration is for what GMC calls "maximum street performance" and includes big 20-inch wheels. The NHT geometry is designed for Sierra owners who need to tow heavier trailers.

The SLT Crew Cab 4x2 we drove was equipped with the Vortec Max 6.0-liter V8 engine, and a 3.75 rear axle. It was fitted with Stabilitrak, side-curtain airbags, a locking rear differential, and a convenience package that includes adjustable pedals, remote vehicle starting system and rear park assist. The SLT we drove had the NHT suspension designed for maximum capacity trailering, with a special steering gear, shock absorbers, rear axle and tires.

The suspension was comfortable and did a good job of isolating the bangs and bumps as we motored along gravel roads, with lots of good-sized rocks, through the Arizona desert north of Phoenix.

But the truck also was comfortable and fully capable of being driven fairly aggressively on narrow paved roads that twisted up the Yarnell Grade and on through the mountains as we took the scenic back way into Prescott.

One of the trucks we drove had its bed loaded with heavy cargo and the brakes were good enough that nothing dramatic happened when we had to make a hard and fast stop.