Nothing at all.
This is the most comfortable vehicle that I have ever driven. Handles smoothly with great turning radius. I have never felt safer on the road with all of the additional safety features!
V8power is unsurpassed as is the towing package (we have a 25ft. boat and haul two horses).
I have one of these also, and so far so good.
This thing can turn on a dime and rides so smoothly.
I put a after-market K&N intake system on, along with some headers, dual exhaust, and different fuel lines, and now my gas mileage is a lot better. At first this truck drank gas and had never seen a gas station it didn't like. Now just driving around the city, the needle really doesn't move.
I recommend if you get any of Chevrolet's massive suv's i.e. Avalanche, Tahoe, Suburban, Yukon, etc. Get some headers and an after-market intake system. It will help immensely. Otherwise, prepare to drop close to 80-100 bucks in it a week.
Nothing is broken and the 5.3 runs strong. At times there is hesitation, but it's my fault for using 89 octane from a cheap station. So for now all is well... we will see how it is in a year or so.