I was there shortly after it opened, about 5 years ago, and it was a very nice property, so it should still be in very good shape.
The pools and beach were fine. It was one of the only real beaches on the island - it's a quite rocky geography and there's not much beach/sandy bottom ocean around the island. I suspect the sand at the Marriott was imported - it was fairly expansive.
I felt safe on the island - it's at the very beginning of commercial development, way behind Grand Cayman, Jamaica, USVI, etc. That also meant there was nothing in walking distance, though that may have changed. I would suggest renting a car so you can get out and about on your vacation.
If you do want to stay on property, the restaurants were decent, iirc, but we only used them once or twice.
As with most resorts, there is no lounge.
We had fun - certainly a different experience than the big tourist islands when you are driving down the road to a beach through cows, monkeys, goats, etc., you feed the monkeys while on the beach, and put your beach chair down about 15 feet from a 700lb pig.
You can get a small feel for what we saw here -
http://richs.smugmug.com/gallery/510...50453235_5Ng9n
The second picture has the Marriott beach out in the distance. The last picture is of Nevis - worth the day trip. (Say hi to Elvis for us, if he's still sailing

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