Had an interesting conversation with a bus driver at National at ORD--I formerly lived there and fly through frequently and sometimes rent cars. Anyway, I complained about what a mess the National compound is (since they don't have numbered slots, they kind of park any old way) and she agreed, saying that that was a big complaint with people renting from NAT at ORD. Except for Dollar, the experiences (on airport)at ORD are pretty similar.