Short answer: We loved it. Within the first hour of being there, my husband and I agreed that we were not going to have enough time on this island because we could tell it was awesome.
We flew into San Juan around 1:15 pm and then waited for what seemed forever to get our luggage. I was pretty convinced we would not make our flight out of Isla Verde since we didn't get on a cab until 30 minutes before our flight was supposed to take off. I asked the cab driver and told him my concerns, but he soon told me to calm down because it would only take us about 10 minutes to get there and that he knew if it took us longer we could always call Vieques AirLink and that they would very likely wait for us a few minutes if we were running late. As promised we made it right on time and we still waited around 20 minutes to board. I recommend the Isla Verde airport. It really is very close and the $20 cab ride is worth saving at least $100 per person per flight.
Once we got to Vieques the house manager picked us up and drove us to Maritza's to pick up our jeep. Like others have said, while a jeep may seem excessive, it was definitely nice to have and more than one local told us we had made the right choice in renting it and we had a great time driving around with the top off.
The next morning we were headed to dive with Isla Nena Scuba. Great company, very easy to work with. They answered the many, many questions we had before booking and made the process very easy. The dive was amazing and I'll be reviewing their company separately.
On our last day we went to the beaches and neither my husband or I have ever seen beaches as beautiful as these.
While there we ate at TinBox, Duffy's, Trade Winds (for breakfast and dinner), Bili's, and Noche. All of them were amazing. We can have pretty high expectations for food and there was nothing here that let us down. The shark wrap at Duffy's was very spicy and we had a hard time finishing it, but even then we still thought it was really good.
We tried to make it to Playa Negra on two different days, but both days we were met with a pack of horses right at the entrance of the beach. Since a few of the mares had their foals, we didn't want to risk upsetting them and after waiting a while for them to move we decided to just walk back. Oh well, we'll just have to try again on our next trip.
I would recommend to make sure you spend at least a weekend day there. That's really our only regret (well, that and not spending more time there overall). There are a few things and restaurants that seem to be only open during the weekend and we were bummed to miss out on them because we left on a Friday morning.
I would also ask that as you go to the different beaches you make sure to take some trash bags so you can take your trash with you. Also while you are there try to pick up some of the trash other people have left behind. It won't really hurt or take that much of your time and perhaps if we all do this then the beaches can remain as beautiful as they are now.
Vieques is amazing. I wish I could describe it better but I can't even come up with words that would truly summarize what an awesome vacation it was. We can't wait to be back.