We recently returned from 2 weeks at Marazul Dive Resort near Westpunt. It is not a "resort" in the true sense of the word, nor does it have a dive shop on site. Rather it is a collection of privately owned condo's, most of which are waterfront. It is a perfect place to stay it you like to have your own self contained apartment; very secure as the property access is gated. The view is lovely and the sunsets stunning. You do need to drive a few minutes to access most of the restaurants in the area with the exception of Rancho El Sobrino which is right next door. If you like to cook in, we did most of our grocery shopping in Willemsted, but were certainly able to get groceries at the stores in Barber and Terra Cora. Most of the units have charcoal barbecures to use..... and if you like eating fish, you can buy it right from the fishermen as they come in the cove at Playa Grandi, literally just a couple of minutes down the road you can see it from the front of the condo.
Marazul has a great house reef you access from stairs cut into the rock. It does require a little effort going up and down but well worth the workout.
We did the majority of our diving with Go West (both tank rentals for shore diving and boat diving with them), an excellent dive operator. I highly recommend the Thursday afternoon Lionfish hunt and dinner.
We also rented tanks from the dive shops at Pureto Mari, Cas Abou and Playa Langun. All of these operators were very helpful and economical to rent tanks from.
Enjoy your trip!