A refreshing escape!
It's beautiful, and one of the only free things to do on Paradise Island! We walked there twice during our stay, and only saw 10 or less people there both times. The arches are all covered with vines with beautiful blossoms. The atmosphere is very peaceful (except when the booze cruise sails by) and refreshing, with a view of the harbor.
I don't know much about the place other than it's a French monastary brought over piece by piece. There's no tours, so you'll have to do your own research.
It's not very large - takes probably about 15 min. to explore. It's just nice to sit and absorb the peacefulness. Anyone who enjoys architecture and some history would like the Cloisters. I'd recommend it for a nice break from the crowds.