I rented from Aruba Royal Car Rental and they were fine (they picked me up on time, had the car seat that I ordered, the vehicle was OK etc). I believe they offer the Suzuki XL-7 for $85 per day/$225 for three days/$395 for a week.
I should also point out that you should make sure that you reserve your car before you go down (i.e. to ensure that you get the vehicle that you want). Furthermore, whatever type of vehicle you end up renting, make sure that it is a 4X4 if you intend to go through through Arikok Park/the rest of the other side of the island. Indeed, I think one of those 15 passenger vans would have trouble getting to the Natural Pool.