Happy?? Oh yeah!
We couldn't be happier with our Yukon. We've only got 7,500 miles on it, and about 1/2 of that towing, but it is an awesome tow rig. The Quadrasteer is really unique and well worth it. Order it now, as I've heard unofficially that GM is dropping it in the '06 model year. We'll either have something very sought after in 5 years or not.
The thing I like the most is the way the SUV drives in tight spaces. You forget how big it is, and just pull in, out or around. My wife never gets out of it without saying, "I love this car."
With the 4.10 gears our Yukon is getting minimum 11.5 towing, a little better without air and on the level. Solo as high as 16+.
We've had the phantom "Service 4-wheel steering" announcement too, and the dealer was unable to diagnose. It just goes away when you restart the car. The dealer suggested if it happens again, to swing by a GM dealer without turning off the engine and they might be able to pull a code. I'm not concerned about it.
I had one close call making a u-turn in a driveway. When I backed out into the street, I cut it too tight, and nearly hit my grand daughter's car parked next to the driveway. It REALLY turns tight! We do kick it into 2 wheel sometimes when backing up to our trailer so it doesn't over steer.
Long reply, bottom line....I LOVE Quadrasteer!