As owner of Unit A 3, ground floor studio, I think i am qualified to answer this question. YES, at times if your back door or windows are open you can hear the humm of the conpressors in the background. It is not loud and with the a/c on you hear nothing. As far as noise from BDA, nothing, nor from the restaurant at Den Lamen right next door. A building is great as you are only 15 seconds from the dive pier and Bari Reef. My unit is one of the closest to the water so you have a wonderful view of Klein Bonaire and the sunsets. ALL units at Sand Dollar are oceanfront and most owners take great pride in their units. We are divers also! Another nice thing about A building is that you are so close to Lovers Ice Cream, MCB Bank, Chat n Browse internet and Sand Dollar grocery.
Please let me know if I can answer any other questions you may have. Have a great trip, I am sure you will like Sand Dollar.