As a UK based Flyertalker, I'm seeking some guidance from those of you more familiar with the US Avis network. I'm looking to book a Premium SUV (like I normally do) from IAD for September next year but I've noticed that there is now a Premium Elite SUV option. From those of you familiar with the US car market, what are the differences between the two classes of vehicle? Which class would you book/recommend?

Thanks in advance.