The Atlantis Copacabana exceeded my expectations for a few reasons.

First, the location is great. It is about 5 blocks from either Ipanema or Copacabana beach. Both beach neighborhoods are have many restaurants and bars as well as for stores, drug stores, and fast food places. Everything is within a 5-10 minute walk. The neighborhood is also mostly residential. I felt safe walking around alone, but I wouldn't recommend it at night.

Second, the hotel was much cleaner and bigger than I expected. The bathrooms were tiled with a marble-like material and the room floors were a hardwood laminate. Don't expect the Ritz, but it's definitely cleaner than US motels. As for size, for 163 R (around 80 USD) I got a double room with two single beds that was around 30 feet long with a small table. There was a small TV in the corner with a few channels that played English programs and there was a mini fridge to keep my drinks, snacks, and leftovers.

These two things were my priorities in booking a hotel but I want to note some other nice things Atlantis had to offer. First, the view onto Copacabana from the rooftop pool/hang out were incredible. It's a relatively high building for the area. The pool looks also recently remodeled and there is a wet bar during the day. Second, the breakfast was pretty good. Only eggs and sausages (hot dogs there) for hot food, but there are numerous fresh fruits, juices, baked breads, and cold cuts. My mouth waters thinking about it. Lastly, they have a person staffed at the desk 24 hours, which is nice when you show up at 4 AM and you've misplaced your key.

Overall, I highly recommend this place for anyone looking for a 3-4 star place on a budget.

Some final tips:
1) Stock the fridge with your own drinks, it's the size of the bigger mini fridges
2) Shop at Zona Sol down the street. It's the cheapest Zona Sol in the area. Don't go to Shell on the corner, it's a rip off.
3) They have white vans that drive up and down the main streets (like Atlantica) that will bring you (with a bunch of other random people) where you'd like to go for 2 R. It's one option between a cab and a bus.