I have the opportunity to purchase a Gravely Pro 300 50" walk behind with a trac vac system ( shreds everything you throw at it ). The mower seems to be in very good working condition, hydraulics are strong. The hours are unknown as this one doesn't have a meter. This is a one owner and he's never had any problems with it. This has the 14hp Kawasaki engine and a I believe a briggs engine running the trac vac. This also has oversize tires on it. It works great. Is $650.00 a good deal? He's asking $850.00 but will take 650.00 for it. All thoughts appreciated.