I need to know which one is the best car out of these three.
The choice between the three cars is tough. If you want a traditional comfortable and a chauffeur-driven luxury sedan, the Mercedes-Benz S Class is the way to go. However, if you are looking for a luxury sedan that is more driver-centric, you should prefer the BMW 7-Series. If you are looking for a luxury sedan that has the most advanced technology, the best choice for you would be the Audi A8.