Look around the 16k range and offer 13-14k... YOu will find some 10 and 11 and maybe 12s with 100 k on it, Your Price range Hell I found a 13 yukon slt that was 45k miles for 16k not too long ago... Since they just released the latest 21 style, so every time body years change there is a slight drop... I traded in an 03 tahoe 4.8 on my burb... loved my lil tahoe, good ole gal who did me right... The burb was 18k and had 97k miles.. So they are out there.. Only reason I actually like the mid packages in the Xl/burb platform is the slt and lt gave you front heated seats I think starting in 12 as a standard. The mid line vehicles with less stuff, is cheaper to fix... One reason I have kept my burb and not upgraded is I don't like Mag ride or air shocks cause that is expensive fixes when they fail... But don't let that little thing sway you from buying something you like and is a good solid truck.. Look at carfax report, alot of vehicles with over 100k already have shocks and a few other things done up by that point and you can enjoy the benefit...
They are pretty easy to work on all in all... If you get the tuner like a superchips or diablo etc, you can turn off AFM and save the life of things for sure... The good thing about those is they have code readers built in, so if the CEL comes on you can see what the code is, you can data log to see if the sensor or whatever is really bad...
The XL/ESV/SUburban platforms ride better with the length also there is a ton of storage behind the 3rd row.. The standard Tahoe/Esky/Yukon don't soak up the bumps as well and you can tell a difference, no room behind the 3rd row, BUT they are more nimble in corners, and better braking and the extra weight makes them faster... I highly suggest taking both platforms for a drive, get on freeway, do service streets etc, you will figure out what is more important to you and what you want out of it.
Swath hit the nail on the head for years and differences.. 11 got alot of revamp in the Powertrain with updated parts.. I am with him look for 11 and up if possible in the 5.3 if you go 6.2 then its a bit different. The 07-09 era had peeling door handles, and few other issues. All of them have outside door handles breaking from the mounting bolt, same with cracking dashes etc..
Know the differences,
Base Models... SL/LS,
Mid Models.....SLT/LT, Luxury
Top Models.....Denali, LTZ, Platnium
Be educated, Id say drive about 4 or 5 of each to get a feel for how they drive, etc you can deduct and probably feel and figure out what way to go.. Hell there is a 11 escalade luxury down the road from my house, 60 k miles they were asking 24k on it, so there are deals out there... But the best taken care of piece with the options you want, and don't be stuck to some stuff as you can upgrade most of these to make a base not base anymore.