Does anyone have an opinion on Killbros 475 grain carts? This would be my first cart - will be used for corn/soybeans on around 300-500 acres (depending on how long I keep it). Will be used with a Deere 7720 combine, dumping into 300-500 bushel trucks. Anything to look for, parts problems? Recent auction prices? There are a couple coming up at auctions this weekend, both have scales & lights. THANKS.