A have a JD data point for you .
I had a Scotts 2348 tractor, just traded it in after 20+ years and it was still going strong. It was basically a rebadged JD, with a Kohler Command engine, w hydraulic lifters. IMO the Kohler commands are the best engines Kohler makes. The tractor was trouble free for the first 10 years . In the end, the engine had a bit of blue smoke on cold startup, and I had to do a couple of repairs, mostly to the deck every summer in the past 10-ish years.
Replacing pulleys, some heavy cast iron brackets (Looked like a tank , but they would just snap in half anyway).
The powerflow bagger housing would drag, and that would wear a hole at the bottom. I would repair it by layering hockey tape and epoxy, creating a poor man's version "fiber" glass... The deck anti-scalp wheels near the blower housing would drag and wear down to a nub, and the brackets holding them would easily bend out of shape, esp if I hit something mowing. I was forever bending these back...
but it was still running smooth, vibration free and cutting great. (it is possible that the trouble spot was caused by the rear tire on that side being constantly low).
Another problem I was having trouble with my tires, frequently getting punctured by driving over locust branches and what not.
I put inner tubes in the originally tubeless shells, but those would get also holed eventually. My next door neighbor recommended to put some
heavy duty tire slime with some fiber reinforcement that then would just automatically seal any punctures. I think that works better if there is no inner tube.
I was doing yearly oil changes, with full synthetic oil, and Fram UG filters. I would grease all the grease fittings yearly, and always balance the blades perfectly.
All in all, I was rather happy with the old thing... perhaps less so if I was less handy. Some of the breakage I was able to fix would have cost real money if I had to take it to someone to get worked on.
I changed the hydro fluid once, after the break-in, I think I put M-1 20W50 synthetic motor oil and never looked at it again.
Replaced it w. an Ariens Apex 52" Zt, with the power bagger, and the residential ( FR691) Kawi engine.
Mostly, because I do not have a lot of time these days to either mow, or to work on the mower.