I bought my Sierra used with about 45000 miles on it. It now has 92000. The problems with the power windows are for real. I replaced the driver side motor and I believe that either side could break again at any moment. The transmission went out at about 80000 miles (one of the drums broke). The dash rattles from time to time. Aside from these problems, the truck really has been reliable and enjoyable. The 5.3 has lots of power, but I do notice a difference in the summer with the AC on. I have enjoyed my GMC, but I will look into a ford when buying my next truck (a crew cab), but there is a good chance I will end up back in a GMC or a Chevy.
I really like the fire engine red paint. 5.3 gets the job done.
Improve the quality of the interior. The stereo sound is not very good.