My tractor has had a pretty tough existence to have only 530 hours. I had to replace valves / seats, rings, cylinder liners, and rod bearing at just 190 hours due to the pathetic excuse for an air filter that came with the tractor (NOTE: be sure to replace the factory filter with a Wix or Purolator AS SOON AS YOU CAN, not after some interval of hours). I did all the work for $150 and my time, and it really didn't even take too long to accomplish due to the simplicity of the design. At 325 hours the tractor was rolled (and I mean ROLLED) down a 20 degree incline by my neighbor who had borrowed it. Fortunately he wasn't seriously injured. This incident required a new steering wheel, inner hub for the left rear tire, exhaust manifold, and muffler (total about $200). The tractor ran upside down for a couple minutes before I could shut it off, so I wouldn't be surprised if another engine issue surfaces prematurely. Other than these issues, which have nothing to do with the quality of the tractor, it has been bulletproof. It has moved thousands of yards of dirt, rock, and gravel, and gets plenty of use with a rotary cutter.
The thing I really like about this tractor is I can do pretty much all the maintenance on my own. The parts are widely available and relatively inexpensive. It lacks the refinement of more expensive tractors, but it does what I need it to do and allowed me to keep thousands of $ in my pocket. If you're somewhat mechanically inclined and have the time to turn wrenches occasionally, these are excellent tractors.