Casa Marina is cheaper then both Sosua by the Sea and Bahia Principe. Being a travel agent I am sure that she is trying to get you to stay at one of the other places as the rates are higher.
Bahia Principe is about 1.5 hrs outside of Puerto Plata and a fair distance away from night life and everything else.
Casa Marina is a nice hotel, true some updates could be made, but other then that I would recomend it for sure. Night life, shopping and Sosua beach all right there.
Cheers
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