I went here, and it is true that there is good kiting, but it is a little tricky to launch and the wind can be fickle, or at least it was for me.
I kited in Great Bay. The launch is on a very narrow beach, and you generally need to walk to the North end to setup and launch (away from the hotel's water sports center). Had to tell a couple people that I would be launching and to be alert until I got out of the way. This was the more difficult side of the beach to launch because the wind comes over a high cliff that is about a mile out on this side of the beach and it is lighter and a bit gusty. Once you get out, you need to get to the south side of the bay to get the best wind due to that cliff (when the wind has a little North direction in it). On this side, you need to weave your way through about 20 moored sailboats and dive boats as you head upwind. The best place to actually ride and be free of obstacles is about a mile offshore or a little less. You are still inside the bay where you need to be careful of the somewhat inconsistent wind near the sides of the bay (I actually had my kite drop out of the air once). This would not have been a problem with stronger wind, but it got up to 17-18 mph at the most every day. I was told this year has been extremely light. You can see the best wind is right outside the bay, where it seemed to have another 5-10 mph in it. The problem is that it is 3 miles upwind, and quite an effort to get there when the wind is not strong.
Now, the guys at the hotel's water sports center were really cool and helpful, as most of them kite themselves. They can take you by boat (quickly) to other areas to kite, with Sandy Spit being the best area, where you can ride flat water and waves, as well as do a long downwinder right back to the hotel when done. There is also a nice grass flat close by where the wind is consistent and they teach beginners.
All in all, the specific launch and conditions right at the beach in Great Bay make it somewhat challenging, but a good place once offshore, especially in the stronger winds they typically get. Also, due to the hotel's configuration and layout, your friends/family can sit there in the pool or on the beach without having sand blowing in their face while you ride right in front of them. There are tremendous places if you are willing to drive or take a boat to other launches. There is also another launch (Jessup Bay) that you can easily walk to (2 minutes) if you get a North wind and are comfortable getting up wind of moored boats. Finally, there is Plenty to do other than kite for no wind days and everyone else with you. Soggy Dollar Bar in Jost Van Dyke is one of the greatest bars I have been to.
If anyone is going and has any questions about St. Thomas or the Virgin Islands, feel free to ask on here or send me a private message.