My advice is:
1 Do not believe in the low-mileage theory when buying an american car. A lot of american cars runs great after very high mileage, just like some of our luck friends here has mentioned. Others break down early. Most of the times it is not the engin that break down first.
2 The larger the better. American cars are famous for their power and toughness, which can only be realized in large cars.
3 It is really luck dependent to buy an american car. But it is the same with buying a japanese car, considering the higher price for japanese cars.