The western is great don't get me wrong the stingrays in grand cayman are a once in a life time experience. I just enjoy the extra day at sea getting to the eastern. It makes it seem so much more tropical, also key west I could do without. It would be a fun place to visit as adults(infact we did the keys for our honeymoon and loved it) but it is not the most child friendly atmosphere. When I go on a cruise I want to feel like I am going far away.
both are equally formal.By all means DH can wear his tux!