I already knew St. Maarten having worked there. We walked to get a local bus and for $2.00/person we went to Marigot Bay where we spent most of the day. The locals are very friendly and it feels like a real small island town. There was little tourist trap.
The island is beautiful. Public transportation works well
We took a bus at the dock and for $8.00/person we went to Magens'Bay. (there is an additional $4.00/person to access Magen's Bay.
The beach is beautiful and clean. There is a lot of people close to the bus and taxy area, but it is fairly quiet during the week at the end of the beach
Nassau is probably the worse of the Bahamas Island and the Caribbean, unhappily most of the ships stop there. I would do anything to avoid it. The streets are lined with jewelery and alcohol vending stores.