Yes rent 6months first is a good move as all of us keep repeating here on the forum. This is because when you come to a new place everything are sometimes picture perfect, and you only notice the real life here after some 6months time.
Sosua and Cabarete are different, but if you spend enough time over there- and feel you have seen much of the place you are interested in, then you must decide if you want to buy or rent there sometime as well. The whole idea behind the "rent first" idea is to make you (the investor) to notice the little details, the frustrating noice. The neighbour that has 50 gallinas, or 20 dogs barking all night long. Parties and trafic from the working girls looses its charm very quickly when you have found a life partner and want to enjoy the last paradise on earth.
The list goes on. Noice, crime and weather related changes are the most important details if you ask me.
Of cource there are plenty of nay-sayers. And i understand that, because you can be lucky and get a good place to stay at once. But i personally would not gamble on such a big investment without knowing the area.
Would you buy a house in the US just by pointing a finger on a map, and do not know how it was there?
I hope you understand what i am saying here, since english is not my language.