A taxi is the best way to go anywhere. You can contact Isaira Tours before you go, and they will give you a set price and be at the airport when you arrive. I found them to be a better price than I was quoted at the resort and more comfortable than trying to negotiate with the cab drivers at the airport.
Phone: 809-320-1433 / 574-0062
We had a two-bedroom lock-off unit - which was great because we went with another couple. The rooms could have used a bit of updating, but everything worked well and was clean and comfortable. If there is anything you need, ask for Abel at the RCI desk. He is awesome and will take care of anything you need.
The food and drinks were great. I would recommend bring large plastic cups with you - they have very small cups, and if you are a beer drinker, you may find this frustrating. Many of the other guests had brought their own larger cups.
The service is above average. We tipped about a dollar for maid service and some of the bartenders and waitstaff. I would recommend bringing about $100 in singles and spreading them around a bit. It will go a long way and is very much appreciated. You certainly don't have to, but it is a poor country, and we feel good doing that.