One word: price.

If I weren't under 25, I might have considered going with Dollar on my Florida roadtrip (MIA to suburban NY). For a subcompact, Alamo was $12/day. Hertz was $4.50/day. Dollar would have been $1/day for a midsize. Airport tax not included, of course. A larger car would have likely cost me big gas money, though. I even met a family driving such a Dollar car to NY at an overnight stop in South Carolina, who confirmed the gas mileage kind of sucks (mid 20s at legal 70 mph). In fact, the terms and conditions said, "It may or may not be a midsize car." Translation: We reserve the right to put you into something even bigger. But all the companies do that. If they don't have the unpopular clown car, they don't have. Fair and square.

Dollar was offering the FL drive out deal for a shorter period of time than the others. Alamo seemed to offer it the longest, plus a free GPS for those straying off the interstate. Like Alamo, the drop point would have been at an airport. However, while for Alamo it would have been HPN, the closest corporate Dollar would have been further, EWR. By contrast, Hertz has a convenient neighborhood branch nearby, so in the long run over the course of a week the price difference with Dollar might have evened out a bit. Even more so if I could have used the $35 off weekly PC instead of the underage PC, which would have cut the total Hertz price in half.

Last year Dollar's underage cutoff was 24. So those 24-year-olds with no corporate promo to remove the underage charge had one place where they could go for nothing extra. They've changed it now, with a new underage charge for 24-year-olds, but it's lower than for 21-23.

Dollar's prices are typically lower for franchise locations, but those tend to be relatively sparse. Again, if you have access to one, you might consider it, especially considering the increasingly higher prices and worse service all the companies seem to be inflicting nowadays.

One-ways over short distances over a relatively longer time might be significantly cheaper than with the other companies. One-ways are only allowed between corporate stores, but if these limited possibilities work for you, the price might be the deciding factor.