My wife and I looked at about six properties in Costambar earlier on this year whilst shopping for an apartment. I must say that it was totally different than what we imagined: it was a lot bigger and spread out with, what appeared to us, very little co-operation between developers resulting in a little "towns-within-a-town" feeling about the place.
I asked for DR1'ers views on the area in March
http://www.dr1.com/forums/living/73693-thinking-investing-property-costambar.html
and although the overall feeling seemed to be negative, (especially regarding the access road), I received a number of PM's from very happy visitors & residents who were more than satisfied with the area.
We were very taken with the area, however decided to buy elsewhere.
One of the comments that we overheard whilst we were in the area was that there was a chance of having problems with the beaches being polluted from the industries in Puerto Plata because of the East to West tidal flow, how true this is I don't know but thought it worth mentioning.
Anyway, that my two pennies worth (for what it's worth) !
Regards
Reidy