I have been to all these destinations except the Crystal resort but I have been several times to Atlantis in the Bahamas.
I can say without a doubt the most beautiful beaches are on Aruba and there is alot to do their. This island caters to Americans as this is their biggest market.
It is a 3 hour flight from Miami and has a 7 mile beach strip with hotels and such. No hurricanes either, it is worth some research. I love Atlantis and it is beautiful and as a group we could get a good rate. But be forewarned everything else is very expensive, guessing a Pina Colada may run $10 bucks and a beer over $7.
If you are also looking to do business in Curacao, Aruba is a 15 minute flight away and also a very good place to extend your trip, it is a very different island than Aruba.
Just some thoughts from someone in the area.
Brian