The Audi A8 and the Mercedes-Benz S-Class are both excellent luxury cars, and they have different strengths and weaknesses. Generally, the Audi A8 is considered to be the better car in terms of performance, while the Mercedes-Benz S-Class is considered to be the better car in terms of luxury and interior appointments. Yet, it depends on what you prioritize when renting a luxury car and both cars are excellent choices in Dubai.