Nationals intermediates are Malibu's, G6's and Stratuses. Using Emerald Isle you get pick on the Isle, sometimes there are larger cars there which you get for the intermediate rate. You will get pick of the lot if there are not ant cars in the isle. I have had this happen several times and have always got something much nice for the intermediate rate. If you are not an Emerald Club member, go to Mousesavers for the link to sign up for free.
I have rented from both Dollar and National in Orlando. Both are good to deal with, but National has been better on rates lately.