We had been to Grand Turk before. Some people say there's not much to do and just go to the beach by the ship. But we took a tour one time and I found it interesting. I was wanting to rent a golf cart this time, but didn't plan ahead. We ended up just going to the beach by the ship. The beach is nice but the water was a little cold. We also hung out at the pool by Margaritaville, who's beer/liquor prices gouge you even more than Carnival. I would stay at a resort on this island if the price was right.
La Romana is hard to rate because we didn't stay in the area. We booked an excursion to Santo Domingo through Carnival ($80 per person). I am a history buff so I thought it was very interesting seeing the "Firsts" in the Americas. The drive there and back was long but scenic.
Looks like the cruise lines have this port cornered, so good luck in finding any non-Carnival price gouging excursion when you get off the ship. There are taxis who will take you to places.
We have considered going to the Dominican Republic before because there are some good deals. We've heard good and bad about the place, crime in particular. We had no problems though. We didn't get to see the nice resort areas up close. I couldn't help but compare it to Mexico. The vendors in Santo Domingo are very pushy. Not as pushy as Jamaica, but more so than Mexico. There is a little more language barrier than Mexico. Our guide was very good though. They seem to be really proud of their history, but you can't help but notice the enormous amount of trash everywhere along the roads. I also saw a huge rat at Diego Columbus's house outside. I know of the economic problems, but just seems like this should be a priority if you are going to be getting in tourists.
We took a taxi to Palm Beach, the fee was reasonable. He dropped us off at the Westin hotel and we walked through to the beach. The beach was free, but if you used a chair someone would come up and charge you a few bucks. Make sure they are with the hotel staff. The water was very pretty, one of the better beaches I've seen. It was very windy though with the trade winds and the sand blew a lot. The water was cold at first this time of year but you get used to it. There's lots of beach activities also you can book on the beach.
I liked Aruba even though it has had its problems. It is kind of like Curacao in that there are a lot of modern businesses and franchises. Both places seemed to have their act together as far as Caribbean Islands go. There's some really tall casino hotels near Palm beach that you can see from a distance.
I would stay in Aruba at a resort if we ever find a good deal. We didn't like having to leave that beach and get back on the ship.