It's a nice place and very popular. Just two things to note:

You hit extreme poverty really fast if you go outside the protected resort zones.

The general water supply is contaminated with shit, they break into the mains to get water for their cattle then allow the cattle's shit to wash back into the pipe. All the resorts have their own filtered water supply but outside of that, the water is filled with parasites and everyone you meet will be a carrier. People always say "don't drink the water" but in Dominican republic, it is really important. Highest rate of food poisoning in the world. Even resorts with private water supplies and forced showers for staff have outbreaks from when someone didn't wash their hands or when pools were used by locals and not drained with the filters backwashed.