National, hands down the best. I really like the Aisle where you pick the car you want, no dealing with counter, huge time saver. They also have a good promotions for free days. I'm thinking you get a free day for every 5 rentals, and the free can even be a one way rental. Getting free car day rentals is much better option than their 50 or whatever miles in the various airline programs. They are also having a 1-2-free promotion where you get an additional free day for every two rentals of 2 days, which is on top of the free days you get normally.

Also like Budget as they have some insanely cheap rentals at times, especially weekly rentals. Their fleet of cars are also new nicely equipped cars. Recently they had a promotion where you got a $25 coupon after two rentals. I've had no issues redeeming the coupons on rentals with Budget, with other companies they make it a huge hassle. I don't think they have a program for free days, you just get airline miles, but with the coupons and their low rates you get in effect both. I have found Budget to be pretty much the lowest cost of the majors, and since they share the fleet with Avis, many times it is the same car you would have received from them.

My problem with Hertz are the hassles at the counter where they try to fear sell every overpriced option in the book to you. I'm guessing they are on a commission, as they make a huge deal when you decline. Also my experience has been they have some seriously old cars in their fleet. With National, Budget, Avis the highest mileage I have seen has been 12,000 miles, with most being under 1,000. Hertz is the opposite side of the spectrum, they recently tried to give me one with over 46,000 miles that reeked of smoke. The manager there told me with a straight face that they keep their cars longer because they maintain them better.

I'm guessing most of Hertz business is corporate contract where they can't do add-ons, so when a non contract customer hits the counter they unleash all their sleazy tactics like a band of stereotypical used car or door-to-door salespeople. Their biggest advantage is they are sometimes the only rental car company at smaller airports, and when that is the case the situation is even worse. Did I mention, I'm not a Hertz fan?