Well, some people say Nassau isn't that great and to stay on the ship. However, I'd like to get off and at least wander around a little. DH is interested in Atlantis, but I haven't seen any deals for January. We've never been to Nassau before as we've only sailed on the Magic which doesn't stop in Nassau. We like to get off in every port, it doesn't mean that we stay off the ship all day. It seems like we are usually off for half of the day and then come back for lunch & a swim. Then, depending on if we have any other excursions or shopping to do, we may get back off the ship. There have been a few ports where we just wander around on our own and hardly spend any money.
If you do decide to stay on the ship, you will have a great time. The 4-day cruise is going to seem very short to me because I've only done 7-days. There is so much to do and enjoy on the ship.
If anyone sees a January Atlantis special, please share!