Atlantis was great. We took a water taxi over and just explored on our own. It was the first time (I know it's hard to believe) that I had ever been inside a casino and I finally got to play a slot machine. Didn't do to bad, got $20 in quarters and walked out of there with $67.50, so I was happy.
Sorry I can't help you with Blackbeard's.
Personally if we ever go to Nassau again we will treat it as a day at sea and just stay onboard the ship. The vendors in Nassau are VERY VERY pushy and don't like to take NO for an answer.
We took a carriage tour around town before we headed to Atlantis and I don't think it was worth the $$$ we paid. It was $45 incl tip and it wasn't very interesting. Our guide sat up front driving, facing forward, and talking to us about the history of Nassau, population, crime, justice system and banking, but most of what he said we couldn't hear. It was like listening to a radio that is losing the signal. You hear a bit here and there and try to piece the rest together.
I think the most interesting thing we saw on the tour was a billboard on a building that said, "Protect ya ting, use a rubber everytime" I was cracking up to see that advertised so bluntly. That is an openess that this country might want to think about trying. LOL