I need help in deciding on what mower to buy used. I have called some local shops and people from classifieds. The one I am considering is a 21 HP B&S Craftsman 42" 2001 model for $500. I also found a 17.5 HP VTWIN Murray 46" for $475, MTD 19HP 42" $550, and a Wizard 18 HP 44" that has a 3rd...