The biggest difference among rental firms concerns how rapidly you can rent and return a car. In most cases, the rest of your rental will be fairly similar no matter which firm you use, since all the major rental agencies use new cars and remove them from service after about 20,000 miles.
Agencies speed the rental process in three ways.
First, rental lots can be located close to airline terminals, resulting in a shorter bus ride. Some car rental agencies also offer express pickup services to shorten rental time. This allows you to avoid the line at the rental counter, which can be very busy when many planes have recently arrived. Hertz, Avis, National, and Budget even have programs that allow customers to proceed directly to a car and drive away without waiting in any line. A third feature that can save time is a quick return service.