I've gotta stick with Hertz or Avis and at PHL Hertz seems to be quicker/easier to rent and return from.
I think I'll take a look around the lot next time I am in PHL to see what kind of cars Hertz actually has there. For instance, a Corolla is a C class just like the Mazda 6 (well Corolla is green collection) but I don't really recall seeing many of either cars there. They don't seem to have much of the cars the Hertz website lists they must have the "or similar" types of cars.
I wouldn't want to call Hertz and put a preference on my account that ends up making me get upgraded to an Impala or SUV or something that I don't want or not getting a Mustang/Corvette (not holding my breath) b/c I said foreign cars only. I guess seeing what PHL actually has will be a start - wish I could get a list of all the possible cars and rank them in preference order haha.
When renting C-Intermediate, I'd be fine with Mazda 6, Toyota Corolla, Ford Focus (which is compact), Mustang, Corvette (ha), Saturn SUV, etc.
I would rather not have any big cars (Camry, Impala, Gran Marquis, Town Car, Pontiac G6, minivans, large SUV's, Mazda 5, etc.