The A8 is Audi's largest sedan, designed to take on the big-sedan competition from Mercedes-Benz and BMW. Like the Benz and the Bimmer, the A8 is fast, roomy, and exceptionally comfortable. It rides like a luxury car, yet handles like a sports sedan. Extremely stable, it tracks rock-steady at super-legal speeds. The same is true, of course, for the competition. But the A8 brings a unique personality to this class. It begins with its styling: Spare, clean and aerodynamically functional, the Audi doesn't have a single line on it that it absolutely does not need. Some buyers might find the A8 plain, but we like its quiet conservatism. The analogous Mercedes and BMW look a bit forced, by comparison. Underneath those sleek lines, the Audi offers unique lightweight aluminum construction that provides best-in-class crash protection. And of course it's the only car in this class with full-time quattro all-wheel drive. That provides a measure of security and outright grip that is only available with the four-circle badge.