Just based on what I've seen around shops, I wouldn't buy it unless it is just to good of a deal to pass up. I'm a fan of buying commercial if you can or atleast the home-owner versions you now see with welded decks. I just feel like buying a used home-owners model would be taking a huge chance on your part and this of course is without me seeing the unit, but with 500 hours I think you will be replacing some parts before long like deck spindles, ect. if they haven't already been replaced. My problem with buying non-commercial used is you usually have no idea as to if it was abused, I'd buy one new because then I'd know how it was treated before I got it.
