We've rented a couple times from Discount Mobility\Florida Van Rentals. They are very nice. It is also pretty convenient. The transaction takes place at the Hyatt in the airport. They drop off the van with the valet and you just pick it up there. We did have to wait for about 20 minutes last time because they were running behind. We probably should have called them right as we got off the plane to get a head start.
Then you just drop it back off at the valet, which is nice because the valet can help you with your luggage to the airline desk.
The vans we used were rear-entry and in pretty good shape. Overall, they are not perfect, but I would recommend them. Also, they did have the best price, about $600 for a week, before taxes and fees.
WLL