The Audi Q7 has been a second tier player in a crowded segment of luxury crossovers, but according to Cars.com reviewer Bill Jackson the diesel version of the Q7 manages to distinguish itself with a sure-footed, muscular ride that gives any driver a reason to smile. Yet the Audi has a few marks against it, one of which is a deal-breaker for Jackson. To find out what that is and if it will keep you from even test-driving a Q7, read his full review.