I have rented from Aruba Royal, Amigo, American and all are equally okay....I usually jump onto the rental adds on this website and pick the one that is offering the best deal. Right now Amigo is offering a small suv for 273 a week....not a bad deal.
Just make sure you print out the confirmation so if they try to give you a different price you have proof of the price...that did happen once but it wasn't at Amigo. You usually will also get a 5% spiff if when you return the vehicle you pay in cash.......Good LucK

Aruba, my home away from home !!