For diving I use Unique water sports of Aruba, you can find them on trip advisor. They are located in the high rise section hotel area. Between the Hilton and RIU Hotel. Ive stayed at the Hilton when it was called Radisson and now i own a timeshare at the Divi Phoenix. All hotels in Aruba are top notch for thre most part you cant go wrong staying there and food all over is excellent. Aruba diving is decent, its no Bonaire. The Antillla is a must as in the Renaissance airplanes and the Jane C ship wreck. As for dive shops there are a good amount so picking one with positive reviews that is near your hotel is the key IMO. Its not worth using a shop located in downtown when ur staying in the high rise area. Traffic can be very bad at times and a long commute isnt worth it when there are dive shops every 3-4 hotels apart. The boat rides to the sites can be 35-45 minutes each way too.