I think the National status is most useful. The corporate code from having the Amex gets you 10% off, but with a little searching you can find better ones with great discounts. You pay a car size less than you purchase.(I believe up to premium) When you rent at least a Midsize you can choose any car from the Executive Selection(if the location has one) which also can have some nice cars, such as Premium, SUV's and the occasional Luxury.