Haven't stayed there but seen it.
The Simpson Bay area is pretty developed and Kitschy...however, as others have pointed out, there are a few good eateries, casinos, and movie theatre's within walking distance. Best food on the island is, IMO, in Grand Case, Marigot, or Cole Bay, however. The Cafe Atlantico, an excellent bakery with perhaps the world's best flan, is about 10 minutes walk just over the Simpson bay bridge.
Beach at the Atrium is not the best, but the Atrium itself is about a one minute walk from Welfare Road, where you can flag down a jitney which will take you to
Mullet Bay Beach for a buck..or go the other way directly into Phillipsburg.
You'll need to make a bus change to get into Marigot, and two to go to Grand Case...
Some, probably at least half, of the rooms at the Atrium do NOT face the water.