Atlantis is awesome! We spent a day there last August when the Wonder was docked at Nassau. The pools and waterpark are great. The food is VERY expensive and not all that great.
As for staying on points...Well, that is usually a lot harder done than said. There aren't a whole lot of trades deposited by Harborside owners. There are some who even have a hard time using their ownership at Atlantis.
I would suggest looking to pay cash for a stay there. They have a lot of good deals on stays. Check travelzoo.com weekly for any specials that are being run.