I rented from National during our trip there in October. I'm an Executive Club member, which at least in the US, lets me choose the vehicle I want for basically paying the intermediate rate. That didn't happen in Aruba, I ended up with a Mitsubishi Lancer. It was definitely larger than the Yaris's and other small vehicles commonplace in Aruba. Except for the car rental companies that bring the car to you, they all seemed to be right across the entrance from the airport (ie. less than 100' from the doors).
And if there was a question, I'd say yes, definitely get a rental car. Prices weren't prices weren't bad, driving is easy, and there are enough places worth driviing to that it's better than trying to do taxi's everywhere.
Jeff