As I write this I am in Culebra
and it would be very difficult to argue with anything that was said recommending Culebra and if you are coming from the East (Virgins) I would say Culebra is your best bet. If you are sailing East along the South coast of P R about half way along the coast I think you would not be disappointed if you stopped at Salinas. Easy car rental if you are willing to drive to airport
to drop off/pick up plus friendly and very safe community of live aboard and transients.