Yes, we have. Yes, there was a formal night & they sprung a second one on us! I'd only brought one formal, so I went shopping at Nassau for another one. They also had a "pirate" night. Others has cute costumes, we didn't know about it & brought nothing for it. Dinner linens were pirate material & the food was in a Caribbean flare that night.
We LOVED Castaway Cay! There's a separate beach for each thing! They have a tram thing that you can use to go all the way out to the far end to the adult beach. It has a bar there. My prince enjoyed playing with the rays while I "caught some". (sunbathed). They have things to rent there. It's got a cafe style food court that has great BBQ'd stuff. There's also a handful of small shops, but other than Castaway stuff they didn't have much. While there plan to spend some time on each beach. I think they have jet skis to rent. I'd sign up for any rentals you can before or on the ship.
Palos wasn't really worth it to me. It was funny.... our waiter was Asia & trying to have an Italian accent to go with the theme. I couldn't understand him at all! The food was good, but I liked the other stuff even better.
We always prefer late dining. If you get hungry earlier, you can hit the cafe or whatever. Having a later dinner means you listen to fewer tried cranky kids. The MAIN reason we like it is because there's no rush after a day on land. Getting back at 5 could mean no time to primp! So it makes it more leisurely to get all gussied up.
We just shopped in Nassau after a helicopter ride. There's an island there for playing with rays & dolphins that we wanted to do. Your choices there are to go to the Atlantis Paradise Resort to play on HUGE water slides & shop & eat. Go out to the island by ferry or helicopter to swim with rays & dolphins. Walk around & have people begging to braid your hair or sell your jewelry. Or the other things on their excursion list. Snorkeling is always good!
Our next cruise will be Disney. I loved it! I want to do the 7 day one.
If possible, I'd recommend a stateroom with a balcony. Especially if you've never been on a ship. That way you can get out in the fresh air if you get queasy. We had a suite & loved it. The staff/crew/cast members were wonderful all over the ship. The shows were great.
These are the island at Nassau where you can swim with rays & dolphins & PART of the Atlantis Paradise resort water park thing. It's HUGE. A bit too far to walk, so sign up for transportation if you go.