Went went couple months ago. It's a nice FS, but not a great FS compared to the others. FlyerTalk's review is definitely more reliable than TripAdvisor's IMHO.
We flew into St Kitts, so we had to take a boat there. They'd a nice big boat and a regular smaller one. I went on the smaller ones both ways, a bit choppier than expected.
The room / services / pools / spa are top notched. The downside is the food, just not good. Unless you rent a car, your selection is limited. People raved about Sunshine, but I found their prices outrageous.
I was there when there is a large convention. Tons of people in suits and shirts. I probably won't be happy if I came here for a quiet honeymoon.

But I think FS Nevis is still worth the trip. A good place for a getaway.