I returned a car yesterday and the amount looked high so I double checked the reservation. Somehow, they managed to bill me for the car class I took from the Executive Emerald aisle, rather than the full size I reserved (about $100 difference) which is what Emerald promises. I then went back to the last 10 reservations (all 2011 for me) and found similar errors on some but not all of them. A few were for just a few dollars, some were quite a bit more. The customer service person was great, and they managed to fix it all up on the same call. If you rent from Emerald Aisle, be aware that their system isn't all it should be and check your reserved rate against the billed rate.