My family (my wife and I, my parents and my wife's mother who are in their early 60s, and my wife's grandmother (mid 80's)) went to Sea Island Resort for 6 days for Christmas 2007. I know it sounds like a motley crew of all ages but the six of us had a great time. Some of us have been there before and enjoyed it just as much this time. My wife and I and my parents rented a 4 bedroom cottage (house) on Sea Island while her mother and grandmother stayed in a room at the Cloister. First off everything is expensive so make your peace with that before you even decide to go. The newly redone Cloister is very nice and had great amenties and a wonderful feel. Several times when I would ask for assistance with my Grandmother in law I would get a response from the staff that they "were new here" and would get someone who knew exactly how to take care of my problem. We got the impression that several folks were new and I guess at a resort like Sea Island that is their biggest problem is keeping the trained staff there so that turnover doesn't sour someone's experiance. The four of us who stayed in the cottage very much liked having a house (which costs the same per night as a room at the Cloister of the Lodge) where we could have more space and not feel weird for walking out of our bedroom in our pajamas. If I were doing it again I would definitely do the cottage over the Cloister or the Lodge because you get to use all of the amenties regardless of where you stay.
We ate in 100 Hudson, Colt & Allison, the beach club, and at the River bar and enjoyed them all. Again, expensive but very good with great atmosphere and views at some. Our favorite thing to do was to head over to the Lodge at sunset and hear the bagpiper play while having cocktails and snacks. It's truly a great experiance and fun time together.
My father and I played the Seaside course which was fantastic and also shot trap at the shooting school which were both very glad we did one morning. My wife and I played tennis and she also enjoyed the spa for half a day.
Sea Island, The Cloister, and The Lodge are truly great places and I'm glad that they're still here for families to enjoy. Are there cheaper places that do very close to the same thing, yes, but that is for each person to decide where they place their priorities. I'm sure we'll go back to Sea Island sometime, but I can say that there are things there (as there are at every nice resort) that I will never forget and I think that is what you go for.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC