I have had both and the new body style and perfer the 01-02 over the 03-06. But make sure it has Hydro boost braking that's the only real issues with the 01 & 02 year models that and the radio is a Din & a half , the mirrors don't power fold and no steering wheel controls.
You can get the dash bezel to make it a double din for real cheap or trim yours. The power fold mirrors can be added, I am seeing about swapping to the newer Steering wheel and using the new wire harness.
The buttons and swiths in the 03 and up the wear out and IMO that's when GM started to have so issues with Finances.
Now depending on what you want it for the Yukons can come with a 6.0L which is a night and day difference power and performance wise.
I looked at a 2003,the seats and interior was pretty good,but first thing I noticed were a lot of worn-out buttons on the dash,that really looked like junk.And there were so many options and accessories,like the automatic seat adjustment thing,that just looks like another thing to be a nightmare when it goes bad.I am sure that I can live without the power fold and a whole lot of other stuff.
Thanks for that about the hydroboost.What do the others have...vacuum brakes?
I want the 5.3 engine,the 6.0 would just burn more gas for me.
I may end up with 2003-2006,but if I find a 2001 with low mileage,I want to be sure that's a good thing.