I've owned a 1999 Yukon SLE for 3 years now. It has been a great investment. Took it in for a tune up at 83k and much to my surprise, the truck was low on anti freeze. Upon closer inspection, intake manifold gasket problem. Why should this occur? I've owned V8's for years and NEVER experienced this problem prior to the vehicle reaching 150K miles.
One of my co-workers owns a '99 Yukon SLE with all options. I drove it one day when it only had 109000 miles on it. At that point, she had already replaced the fuel pump ($$$), countless door lock solenoids, door handles, and window regulators. The driver's interior door handle was already broken meaning you had to put down the window (assuming it worked) and reach around to the outside handle to get out. Also, it drove like crap. All of the front suspension parts seemed to be badly worn and the brake pedal response was terrible! I had to press the pedal all the way to the floor to stop. This vehicle did not inspire much confidence when I drove it and I was not impressed with the ticky-tacky interior bits. The sound system was excellent however. One day recently, she came to work and told me that her turn signals, brake lights, and the A/C blower fan had all stopped working within a week of each other. Tsk tsk, GMC.
I own a 1999 Yukon SLE, I bought it from a young lady 3 years ago.
At first I thought that I'd have to fix everything from A-Z on it, assuming that she neglected some maintenance on the vehicle. But to my surprise the truck was well kept, extraordinarily clean inside and out, engine parts still looked new and runs A-1. So far all I replaced was a starter, battery, U-joint and the tail light circuit board, I have it diagnosed a lot just in case, but my mechanic always gives me a thumbs up.
All I can say is be good to it and it might last a lifetime.