I might be a little bit off-topic below since I am a generation or two older, but to answer the op question I would totally recommend a K2XX over a GMT900. Mostly because of the more updated powertrain and interior quality improvements. I’ve read in a few different places by a 2016 and up SUV as GM made a bunch of improvements between 2015 to 2016
I own 3 platforms. 2 Trucks and 1 Suburban. Both trucks have camper shells so they kind of look like an oversized SUV.
I like the looks of the Chevy GMT 900 platform but they just feel so cheap inside. You have to remember that platform is pre-and post bankruptcy years. The powertrain seems pretty stout but looking at a GMT 800 and 900 several years ago the 800 just felt better built and more comfortable.
That said I would buy a 2009 Tahoe 6.2 L four-wheel-drive in a heartbeat! But the 6.2 is a 1 year option and those are hard to find in nice condition and not miled out. Yes I know I could just get a GMC SUV with 6.2 but I don’t want the full time all-wheel-drive.
My GMT400 97 k1500 was purchased brand new in 1997 and has been in the family ever since. Current 218,000 miles, original transmission and engine. It towed 6500 pounds which was the max. The first 2 years in the Colorado mountains after that it’s been unloaded and daily driver. This rides the smoothest out of all three and has been rocksolid reliable. The 5.7 350 pulls down better highway mileage then the suburban with the torque-less wonder 5.3. The 5.3 does pull harder than the 5.7 but only in the higher RPM range but I prefer the lower RPM torque from the 5.7. I had the truck weighed and it weighs 5520 pounds with the snug top and a full tank of fuel which should be the same or very close to the 2003 suburban weight wise.
The 2003 suburban has very comfortable seats. It’s a little bit more comfortable than the plush GMT400 seats. Lots of electrical and electronic problems in the suburban. I’ve had to replace the radio due to not working when cold. I still get random codes of communication issues with rear seat audio and an annoying buzzing from the rear speakers when it’s really cold out until the cabin warms up. I am now self certified in diagnosing, troubleshooting and replacing HVAC actuators for the front and rear climate control.
The burb has 173k on it, original LM7 5.3 which runs great. Transmission was replaced at 150k. The Burb rides really well it’s almost a tossup between this and the 97 on ride quality. Interior quality they are about the same. Chassis, you can tell where GM cheaped out like having to replace the front wheel bearing hubs on the 2003 where 97 is original. Heater hose quick disconnects, window regulators are sketchy, little stuff like that.
Purchased my 2018 Sierra brand new. It’s been great except for odd messages occasionally on startup like service stability track, service four-wheel-drive. Replace negative battery cable which helped due to high resistance, but will still get these messages every few months randomly. The backlight for the climate control buttons to no longer light up and that’s sad for a six-year-old truck that gets driven every other week.
If you have an eight speed flush out the original fluid with the new blue label mobil one. I did this at 20,000 miles and besides some clunky shifting in rolling stop and go traffic no problems and no metal shavings or any thing else to indicate transmission issues. The front seats are hard as a rock and remain hard. Five years later the rear seat has much more give and is almost more comfortable than the fronts to sit in.
Favorite thing is the 6.2 L and the eight speed has the gear ratios just right I’ve towed my 4000 pounds enclosed trailer with all three vehicles and of course this one tows it the best. The big 6.2 and double the gears of the other trucks = win.
I like the looks of the latest generation trucks and SUVs and would buy one if I wanted to spend that much money. Independent rear suspension no solid axle bothered me, but it’s probably fine unless you’re doing a lot of heavy towing.