I have a 717A, with five seasons and 1850 service hours behind it. It is my first and only ZTR, so I don't have any reference with other similar machines.
It has been a very sound machine. I've changed belts one time, and not because one of them broke. I think I made the change at about 1,200 hours. I've changed the hydro filter every off-season (about 400 hours), and refilled with new 15W-40 Amsoil. Engine oil has been changed every 40 hours, filter every 80 hours, 30W Shell Rotella oil. The adjuster for the tension spring on the deck belt is not a good part. The tension bar vibrates when the deck engaged, and the small loop wore through quickly. I just replaced it with an eye-bolt, and that has been a good solution. Also, the tang on the tension bar broke this past season, and I rebuilt with a bolt. not a big repair at all. Two deck idler pulleys have worn the bearings, and have been replaced recently. I do a lube job every 20 hours.
I consider none of these repairs out of the ordinary, and should be expected. The only design flaw is the OEM adjuster for the tension spring.
The engine has remained strong, although a small oil leak has developed on the bottom end. I suspect it is an crank oil seal, and will be repaired before the 2013 season. The engine is as strong as the day it was new, starts well, runs with good power for a 19hp engine. Only when the machine is working in heavy grass, and traveling on an uphill path, do I need to cut back a bit as it is struggling.
In terms of quality of cut, it is superb. The 7Iron deck does a great job. It leaves a very smooth cut for my cool weather, northern grasses. I use standard OEM blades, and sharpen them about every six hours of operation. A bolt is an easy-off, easy-on procedure for changing blades. I keep the deflector on the discharge chute, and have it on a small chain attached to the end. A hook enables me to raise the deflector to full up position for transport on the trailer. But, just as important, it enables me to adjust the height at the tip for best clipping dispersal. Sometimes the tip is best in the full down position, other times, hooking it up an inch,or two at the tip works better. Working without the deflector, or with it in the full upright position, is not the best for good clipping cover.
In general, I am very pleased with the machine, and would by another if needed.