One thing that most forget to mention, and I am going to tell you, because I don't want people to think poorly of our beautiful country. When you get to the airport, you will go outside, and there will be a hundred baggage porters trying to grab your bags and carry them for you. These people are pushy, and very rude. If you want their help, agree on a price (I think 10 or 15 pesos / bag is good - this is $1 US) before you let him grab your bags, and don't give him any more than agreed upon. If you do not want their help, look at them, and say a VERY FIRM "NO." And keep walking. Do not mistake them for a taxi driver, because taxi drivers will not porter bags. Don't mistake them for someone from your hotel, even if he says he works for the hotel - they will also not porter your bags.
If you let him carry your bags without agreeing on a price, they are going to try to charge you $25 US. And all of a sudden, they will have 6 other porters, ready to back him up. I hate how they do this to tourists, however, this is how they make money - their bread and butter.
If you are harrassed in any way, yell "Policia". It is illegal for anyone in the Dominican to harrass tourists. They will scatter like fleas, because they know that it is illegal.
That is one of the only negative things I can say about the DR. Take care, have a wonderful trip.