I spent about 5 weeks there in 2010.  It's VERY different from St. Martin.  It's a beautiful place unspoiled by american tourism (as of 2010 anyway).  You need to speak French or be really comfortable "faking it".  Rent a car, stay in several places like at least 1 or 2 locales on each wing of the butterfly.  We spent weeks - literally - visiting different beaches.  Also, spend a few days in Marie Galante - it's unreal.