Not sure what the details of the reviews you are reading are. A huge problem with Avis at DCA is that they now are off-site and not at the airport. You have to take a shuttle bus to their location in Crystal City. While the off-site location is not that far away, it does takes additional time when arriving to and leaving from DCA. Also Avis' hours of operation are from 7am-11pm, definitely not convenient if you have an early morning departure or late arrival into DCA.