It is fair to say that since you like Aruba, St. Maarten and St. Thomas, that you like a bit of action, proximity to shopping and restaurants, and generally a no-hassle experience? Of your 4 proposed islands, I would suggest Grand Cayman. The downside is it is pricey but the upside is it is relatively safe, clean and enjoyable. If you stay on Seven Mile Beach, you can walk to restaurants and shopping. The water and beaches are great.
