I do quite a bit of traveling... and this is the only country that I have visited where I had an absolutely miserable time. I would never go back to the DR.
I went with two friends... and stayed at the "Five Star" Catalonia Bavaro Resort.
Although the resort itself was beautiful, we all had a lousy time. Why? We were all sick as dogs! We were so careful about the water... all we drank was bottled water. We brushed our teeth with bottled water. We declined ice in our drinks. We ate no raw food, and only peeled fruit. Yet we all got sicker than sick. In fact, a huge amount of people at the resort told us they were sick as well.
I think the problem is that this is a third world country, and the hygene practices are not like ours. The restaurants were all outdoors, and the food was out in the heat. I saw food handlers in the bathrooms who didn't wash their hands. And.. despite this being a gorgeous resort, there were chickens and roosters running around the grounds!
Speaking of illness, you might want to talk to your doctor about taking chloroqunine as a prophylaxis against malaria.
"Travelers to rural areas of the Dominican Republic are at risk for malaria, with the highest risk in provinces bordering Haiti. In addition, risk in all areas of La Altagracia Province, including Punta Cana and Bavaro Beach."
http://www.cdc.gov/travel/caribean.htm
The DR has also had outbreaks of polio from time to time, (due to its proximity to Haiti) so be sure to check on the cdc site for the latest health info.
Remember too, that this is a very poor country, so there is a crime problem. I was not happy with the fact that there were security guards on the hotel perimeter armed with machine guns!
Dominican Repubic? Never again. I'll take Bermuda!