I bought my Z66 new, it is the best vehicle I have ever owned. I have over 124,00 miles on it, have done no repairs at all, just maintenance. I still have the original brakes and they were checked when I put new tires on a couple of months ago and they still have 65% of the pads left. I have room for 5 people and can carry all their luggage and then some. I didn't buy it for the gas mileage, but I just drove on vacation and got around 19 mpg, and that was both highway and riding around mileage. I cant complain.
Comfort and ride. My mother has a Cadillac that she bought the day before I bought my Avalanche, and my truck rides as good as her car.