We had a wonderful stay at the Banyan Tree Sanctuary. If you read the other reviews and the Sanctuary's own description, you will get a very good idea of the place and whether it is appropriate for you.
The Sanctuary is located at the end of a one mile, one lane road built in to a hillside overlooking the shore; at the beginning the street appears suburban; by the end it appears to be in a tropical forest.
There are a small number of rooms and none of what you would expect in a resort; so if you're coming for that kind of stay you won't find what you're looking for. Actually, that's not quite true--there is a lovely pool, a jacuzzi, and a sauna--but no room service, bar, or gift shop.
Most of the time we had common areas to ourselves since the number of guests is small.
The Sanctuary it is set up for yoga, meditation, and a small number of visitors; it is a small working farm for the partners who run/manage it. For guests, there is a full kitchen where you can make your own coffee/breakfast/meals. Coffee, tea, and some fresh fruits are provided, but anything else you bring in (vegan-friendly food only).
Words like "tranquil" and "serene" recur in the reviews for a reason--it is quiet (well, there are almost always birds chirping), out of the way, and very relaxed. Sunrises and sunsets were particularly lovely.
If that sort of stay sounds good to you, I would very highly recommend Banyan Tree Sanctuary. We were very sad to leave.