GMT400s are still best of the breed on several accounts, IMO. Anything older will require this n that for repairs. Since "there's no demand" for HD suvs as some claim, you'd think they'd be paying you to take them gas hogs, but around here, a Burb like BenK's with low 100s for miles is a $10k rig.
IMO, the GMT 400s generally didn't have any fatal flaws (if you don't get into the 6.5 diesels...) and relatively easy to improve certain aspects, like the dually rear wheel cylinders. I did that cheap mod years ago, it was great.
Only thing better is if you could get a GMT 400 big block K2500 burb with the NV4500 that you could get in the pickups!