Apple
I always use Apple and did use it to Punta Cana last year. We have had very good luck with them. They use charters which although a little cramped, go straight to your destination. We were delayed about an hour on our return, but have heard sometimes longer. The airport in Punta Cana is a charming thatched roof building with little to do if delayed. Patience is key. Punta Cana was wonderful, there is no town, it's all resorts. Where are you planning on staying? The resorts, for the most part are very large, have lots of restaurants, bars, a casino, and their own entertainment. There is really no nightlife outside of the resorts.