i use reserva banc in sosua, next door to super super.
the only fee i get is a fee from my home back for an international transaction, which is about 2 bucks iirc. reserva banc never charges me a fee.
i used that atm, day, and sometimes night, in february, march, april, may, july, october, and november, and have never had a fee.
also, iirc the limit per transaction is 5000 pesos. but then you can do another transaction without starting over. i THINK it was 5000 it may have been 7000