L'Équipe, France's biggest automotive authority compared the top luxury cars against each other. This is similar to the Car and Driver review a few months ago. Here are the results:
1st Place: Mercedes S500 388/420 points
2nd Place: Audi A8 4.2 Quattro 369/420 points
3rd Place: Jaguar XJ8 363/420 points
4th Place: BMW 750i 338/420 points
5th Place: Lexus LS460 299/420 points
Here are the specs most of you care about. I also translated what they said about each car (the main points).
Mercedes S500:
0-100 km/h = 5.4 seconds
100-0 km/h braking distance: 52.4 meters
If there is a car that sets the benchmark for this segment, it's the Mercedes S class. Comfortable, dynamic and well built, the S class also impresses with its refined, silent and powerful V8. For a car of its size, it handles like a sports car. The V8 engine responds nicely to driver input.
Audi A8 4.2 Quattro:
0-100 km/h = 6.4 seconds
100-0 km/h braking distance: 51.3 meters
A solid well made car with an efficient AWD system and the best traction. Despite the aluminum body, the A8 is still a heavy car and coupled with AWD ensures that it does not accelerate as fast. It is equal with the S class in terms of handling, but the comfort could be better.
Jaguar XJ8:
0-100 km/h = 6.0 seconds
100-0 km/h braking distance: 59.3 meters
The Jaguar surprised us the most in this comparison. It handles generally well, but the ride and comfort are top class, but not as good as the Mercedes or Lexus. The engine has character and so does the design inside and out. If you're looking for old luxury, this is the car to get.
BMW 750i:
0-100 km/h = 5.8 seconds
100-0 km/h braking distance: 55.8 meters
Still the sportiest of the bunch, but its age is showing. The V8 engine is a joy to hear and responds on tap to driver input. Comfort is not the strength of the 7 series, it is outclassed by the competition in this department.
Lexus LS460:
0-100 km/h = 6.3 seconds
100-0 km/h braking distance: 67.3 meters
The Lexus is a fine car but it lacks the dynamic capabilities of the Europeans due to the soft suspension. A diesel engine option is non-existent and the brakes are quite weak. It comes however well equipped and can't be beaten in terms of value. Comfort is on the same level as the S class.