Had a Kubota L2250 with over 5,000 hours, and it still ran well.
Then a 2800, had it for 700 hours or so and traded it to buy a 9540.
I've got over 700 hours on the 9540 and not a single problem.
Also, our zero turns get a ton of use and they haven't had a single problem.
Kubota stuff is about as solid as it gets in the world of machinery...