I've never heard much talk about the Daewoo dozers. Since they only produced them for a few years, I'm not sure whether that's a good or bad thing.
$8500 is a nice price for a relatively newer machine like that assuming shape is good. But, my concern would be parts/support. Daewoo (now Doosan) hasn't sold those machines in years and the dealers are rather scarce.
I would suspect you will be on your own wrenching on the thing and scaring up compatible replacement parts from alternative suppliers. Doosan may still stock some parts, but, I'd suspect they're pretty pricey.