I had 2 and tow a lot. A 2010 gl350 towed great and I mean great had about a 32 gal Diesal tank, awesome I could go from NY to Fl with just 1 fill up When not towing.
I used a remote trailer brake system that plugged in the cigarette lighter. The air ride system would level out the ride. It felt very stable like a tank. I did baby this not drive hard like i do on my Jap trucks.
Back then you could get a 100,000 mile 7 year warranty for about $4,400 A must have. Why?
2010 def got filled once every 10k at the service with the oil change not to bad. Things that went wrong That I remember on that one.
Def tank pump went, suspension air bag went, 3 at different times, they would change both front when 1 went or both rear when 1 went. The plastic wood grain inside cracked, they replaced it twice, air bag safety system had a problem also. oil leak inside motor. Def tank cracked.
Got 25 mpg most of the time and 30 plus on trips to Fl. 18 mpg towing easy Down there with about 2,000 in a enclosed trailer. Pulled out tractor when my Tundra would not so plenty of low end power. Towed 6,7k plenty of times.
But after 100k repairs cost so much I got new one in 2014,at 110k they gave me a quote of 9k of crap to fix. I bought a new one they had there for 65k it worked the same but used more def fluid and got less mileage about 22 normal and 16 towing. The first one was loaded up and was 83k so I was happy with the price of the second one. 2014 did not have as many problems. On the 2010 I had the appearance package, crap that had 20” rims and run flat tires. The tires were wide and would last 25k at most, they were GoodYear but made in Germany for that car. Yup $800 each first set had to get from dealer no one else had them $2,400 for tires. They have copy’s now and the price is down.
If cost is a factor buy a Tundra, probably lowest cost to own for 200k miles. About 35,000 for a stripped truck.
if cost is not a big deal a land Cruiser is great a 20 year old Land cruise is still 20k a 20 year old Mercedes is 3,500 the difference is cost to maintain them. If going used a Nissan Armada works great for towing and is reasonable to maintain. It is on a Titan chassis and towed great. I towed the 35’ Fountain back from Fl this year with one, it was fine. It was out of its weight class I know but in the beginning of April no one was pulling over someone with NY plates.