Wife and I celebrated 10 years recently, and we stayed at the atrium for 5 nights. We had a week reservation, but could not take advantage of the entire period. I called in advance to inform the resort that we would be arriving a day late (Sunday vice Saturday). No problems there.
After the 10 minute drive from the Airport to the resort, we checked in. The resort did not standout that much from the other nearby buildings. Another nearby resort was having some major upgrade work though and from a distance, I worried it was the Atrium. I was happy when I realized that the Atrium was not that resort.
The resort has a nice, open lobby. Plenty of plants and small furniture to go with the island decor. A desktop computer with DSL internet was in the lobby and 2 rickety elevators were very close by. The front desk staff was helpful, but wondered why we were a day late. Apparently he didn't get my message; no problem. We were able to check in around 2:30pm. We were given a unit on the third floor (303). We entered to find the housekeeping performing their last minute cleaning. After seeing us, they smiled and quickly finished up.
Our room was clean, odor free, and had an ocean view, although several palm trees blocked all but a few glimpses of the beach. I would recommend getting something on the 4th floor or higher if you really want a good view of the beach. As luck would have it, I had a nice view of the pool. The nearby (1/4 mile) resort construction/repair was easily visible, but did not generate much noise. The unit had a full kitchen with stove top and oven unit, tall fridge, dual kitchen sink, and several cabinets full of dishes. A table with 4 chairs sat right under the TV hutch. A fold out sofa was at the far end of the room, facing the 36 inch LCD television set. Our bedroom had a king size, although very firm, bed, with two in-tables, a chair and dresser. The complimentary safe was a pleasant surprise and was located in the back of the closet.
Our bathroom was clean, modern, but not new. It had a single sink with a toilet and shower/tub combo. It had a bedroom and hallway entrance and plenty of room to handle both of us at once. With only a few cosmetic flaws, this bathroom passed the wife's test with a good score.
We received fresh towels and clean sheets our first 2 days there. The cleaning lady came Wednesday (3rd day), but we were taking it easy so declined her services. We received nothing on Thursday, our final day (but the resort did not know we were leaving). When we left on Friday, they had installed a wireless internet connection in our room. It came with a note stating that all the rooms were going to get wireless internet service in the next few weeks.
The resort parking was easy to get to and we never had to search for a spot. The gate was opened by your room key, and was left up during the day. Security was present most days, if not in the parking garage, then around the lobby and pool. Speaking of which, the pool was small, but adequate. It was close to the restaurant and only about 50 yards from the beach, but was not in direct view. Nothing too fancy. We ate lunch at the resort restaurant, Picantes and had a decent meal and great drinks. $40 for the two of us, including tip.
I must say that the one thing that the Atrium has going is its location. Simpson Bay has tons of restaurants within walking/staggering distance. A couple of casinos, a beach, grocery store, and marina were 10 minutes away by foot. It is easy to get to/from, and isn't right on the main road. Traffic can get backed up around the Simpson bay area pretty easily though.

All-in-all we liked the Atrium. I knew we were not going to get a ritzy, lush resort. I set my expectations accordingly and was pleasantly surprised.
PRO's-- Our room was clean, comfortable, and functional. The staff did their job and helped out when asked. The location can't be beat and really mitigated some of the worries I had about getting around the island.
CON's-- The ocean view was distracted by the nearby construction. We got asked to attend a timeshare presentation (but only once). Many small repairs were going on around the property (i.e.. picnic table repairs, tree replacement/thinning, and pressure washing of the pool areas), but this may have been due to it being the off season.

We would gladly book here again!