I went there approximately 8-10 times between 2001ish and 2015ish. The Cove is beautiful (and expensive), while I would say the villas are your 2nd best bet. Back in the day we used to get "upgraded" to the villas from the main hotel by slipping a $20 bill to the front desk person checking us in. Worked pretty much every time.
(Not sure if it works any longer, though. Probably needs to be a $50 now, LOL.)
Any need to leave the property? That all depends on how long you are staying (my trips were almost always of the 3 to 4 day variety as I live in south Florida), have you ever been to the Bahamas before, and do you enjoy sightseeing? The Atlantis is just over the bridge from Nassau (you will understand what I mean when you get there) and if your trip is going to be for a week then yes, I would plan on spending at least one day into the evening in Nassau. However, I will also say that there is plenty to do on the grounds of the resort to keep you busy for days if you enjoy the following:
- floating around a not-so-lazy river as part of Aquaventure (always enjoyed that river)
- viewing some pretty amazing aquariums (not everyone is into this, but I actually sat there for a couple of hours on multiple occasions, or would walk around looking for different vantage points - the Atlantis aquariums, particularly the main one, are pretty awesome, even though they no longer have the Manta Ray with the 27-foot wing span in there any longer. That Manta was breath-taking to watch).
- beaches and pools with activities usually happening somewhere
- swimming with dolphins in their own man-made Dolphin Cove
- other half-day and full day trips booked through their concierge desk
- shopping (they have shops throughout the main hallways of the resort)
- gambling (both table games and a sports book with a viewing area)
I got lucky enough to play the Ocean golf course once - amazing views, definitely the coolest place I have ever played. But is it worth it? That depends on you... is $269 for a round of golf worth it for a once-in-a-lifetime golfing experience? Some would say yes, others no. Depends on your budget. love of golf, etc... I am happy I did it once, but would be hard pressed to do it again.
One other important note. BE PREPARED: The Atlantis is VERY EXPENSIVE - for EVERYTHING. Budget yourself knowing you will be paying at least double the price for most everything you purchase there: Meals, drinks, rentals, day trips... all of it. They also charge those who are not staying at the resort a "DAILY RESORT FEE" of... get this... $190 per adult, and $95 per child. Definitely NOT for the faint of heart.
Overall though, I would say if you aware of that point that you can have a really relaxing yet wonderful time there. I sure did.
Hope this helps... and have a GREAT TIME!