Regarding the competition on the businessfront, don't bother listening to people's negativity. Look at Gordito's in Caberete, probably one of the most successful restaurants on the North coast, they do mexican and I have never seen any other mexican restaurants in Cabarete. If it was like people said, there would be taco shops all up and down the strip and there isn't one.
Another gem is Mojitos bar on the Cabarete beach, run by an Italian expat. All the other places on the beach may be empty, but these guys are hard to get a table at. They are doing something right....