Just came back from a 7 night stay using the certificate last month... Had a more unique situation as I had MrsL2CTW, mini-L2CTW1, mini-L2CTW2 (4 and 6), as well as their grandma (total of 3 adults and 2 little ones).

Based on all the calls and chats to Atlantis and actual stay, here is what I can say:

• Atlantis allows maximum of 5 people per room; technically 4 adults and 1 child (age 4 and under).
• That said, the award rate allows you to have 2 adults and 2 (or 3) children in the room without extra fee. Any adult(s) over the 2 allowed will be $50/adult/night +tax. I don't suspect there's any way around that; even if you tried to sneak a couple of people in, the room key is programmed to indicate how many wristbands to be given out at the waterpark; and they do monitor that. There are people along the property that I saw would look for guests and their wristbands. No wristband means you are denied access to the waterpark along with parts of the hotel property during certain hours (I suspect during the "cruise ship" guest hours during the day). Casino is of course welcomed to all.
• They still charge a "resort fee" of $50+ night; which is unavoidable. This includes access to the water park/aquarium, 2 bottles of water/day, and high speed wifi internet access for up to 5 devices. If you need to switch devices, you will need to call the IT Helpdesk and give them the last 4 of your MAC address so they can remove it and allow another device to connect. Bottles of water can be collected at any store on the property (including gift shops and restaurants).
• As Gold, there were no benefits (though we did get a few extra certificates for bottles of water). No upgrades available; though to be fair, I did look up room availability during our time there and the place was sold out.
• When you book a room that specifies 2 Queens, I found that it would have a surcharge on the number of points. If you book a room that is "1 King OR 2 Queen", you are charged the standard number of points. Base on my conversations with the hotel, if you book 1K OR 2Q, and indicate you have more than 2 people in your room, they prioritize you to have a room with 2 Queens. However, if you wind up being unlucky and get 1 King, they will provide you a rollaway bed without a fee (there is no space for a rollaway in a standard 2Q room). So save yourself the points and just go with the 1K OR 2Q, unless you absolutely must have a confirmed 2 Queens.
• Prior to the Coral being upped to Cat 8, I would have said Coral since it was newly renovated and 1 category less. However, Coral never had regular room rate, it always required a premium for confirmed 2Q's. It made the total number of points even more expensive than Cat 8 Royal. I decided to just go with Royal using standard number of points.
• Now that they have made Coral into a Cat 8, go with the Royal; the Coral and Beach were built back in the 60's. The incredible (and it truly is incredible) lobby/aquarium is located in the Royal Tower. The Marina Village at Atlantis (food/shops) is closer to Beach and Coral though.
• Waterpark closed at 7PM, even though there was still plenty of sunlight (July; don't know if seasonal hours).
• Water rides (like the 60 foot slide) requires minimum 48"; some rides allow adults to accompany child if they are shorter, but those are mainly for the tube rides.
• Room wise, nothing to write home about. It looks like a regular hotel room with tropical motifs.
• If you take a shuttle, you can pay an additional $10-$15 for a stop at the local supermarket to get groceries. We bought a couple jugs of water and drinks at the grocery store; I originally felt embarrassed having to haul the bags from the grocery store; until I saw multiple bell hops carting 2 or 3 cases of water from other incoming guests (then I didn't feel so ridiculous).
• It is true that food is expensive there: $11 for a can of Spam; $8 for a small plastic container of strawberries; $6 for 1/2 gallon of milk. You can save a few bucks if you want to slum it and bring some noodles/cereal for breakfast/lunch/dinner. That's obviously a personal preference.
• The minifridge in the room is one of those automated ones, so you cannot just empty it out and stash your own stuff. Minifridge rentals are available for $15/day.
• Gratuity is baked into everything you buy/order. All restaurants have tip included.
• There is a meal plan option; however, the cheapest is $85/adult/night + gratuity, and you must purchase it for your entire stay. That alone made it a deal breaker for us as 3 adults would have racked up over $2,100 in food alone (and that was the cheapest plan with 2 meals/day). https://www.atlantisbahamas.com/dining/diningplans
• The service was hit and miss. Met some with great service, and some who were indifferent.
• There are a lot of "excursion" activities that cost money; so depending on your budget and interest, it can add up. Do make reservations at least a few days in advance (prior to arrival is even better). We were unable to book an activity for the little ones 3 days out because they were all booked. This may not be an issue during low season, but for first week of July, it was certainly busy.
• If you eat off-site (less than 10 minute walk past the property) at Anthony's, it is a little bit cheaper. There's also a tiny market and Dunkin Donuts in the same shopping plaza.
• Taking a cab back to Nassau is around $20; ferry is $5/person and you will wait for a long time (up to 20 minutes or more) unless you time it just right and you are one of the last ones to board and the ferry leaves full.
• We limited ourselves to being mainly on the resort, and one day off site. We weren't particularly interested in going elsewhere since the little ones just wanted to play all day at the waterpark.
• As mentioned here, Comfort Suites is a viable alternative if one is looking for a cheaper point of entry to the waterpark. However, for Beach Tower, I did see rates as low as $180/night + resort fee, so may not be all that different.

That's my brain dump for now; feel free to ask any questions while it's still fresh in my mind.

One last item: if anyone is wondering if I would go back, the answer is yes. It certainly is a matter of perspective, but given that my kids were too small to go on the rides, they want to go back when they are tall/old enough and I think it is worth it.The resort grounds itself is amazing and the waterpark/pools/beach are great fun. The kids saw stingrays, hammerhead sharks, sawfish, sea turtles, all while walking the grounds. That doesn't even include the aquarium and underwater tunnels.

I know that the place is expensive, but I consider the property to be more than just a resort with pools. It is a property that has to also pay for specialists in maintaining aquariums, marine animals, waterpark, etc. That means there is a higher overhead; so I am sympathetic to the additional cost involved. Now that I have been there, I can say I see why. But if one doesn't value those things, it's also understandable why it's not worth it.