My daughter has an 04 Tahoe with the 5.7 motor which pulls a 4,900 Mastercraft boat and trailer 5,000 miles per year. Total miles now 38,685. I replaced original rear disc brake pads two wks.ago with orig. AC-Delco pads. No rotor damage. Front pads. were still good. Don't know exactly why as typically fronts wear faster. Rear pads and calipers are massive for good stopping power.
The truck's never been in the shop for any reason but regular service - IE. - oil and filter changes. They decided early on to use synthetic Quaker State 5W-30 in the crankcase because of towing.
I've ridden in my nephew's new full sized Land Rover. The ride and handling can't be compared to the Tahoe.
The 07's are better yet. Coil springs instead of torsion bars in the front. Same multi-link coil spring rear end. I stand 6'4" and have 13AA feet and have more than adequate room in the rear.
In my opinion you're making a solid choice. The 08's will be tuned to operate on regular 87 gasoline or higher octane E-85 fuel. Power increases by 25 hp. but fuel economy drops by 5 mpg.