We had one dinner at Calypso during our week in Kioni and generally the food was fine although nothing to shout about.
However we also visited the cafe next door which has the same owners I think. The coffee here is very good, and great wifi however we were very disappointed with the ice cream they served us. It was just very sweet.
As I've reviewed the ladies loos in all other restaurants I visited in Kioni I feel its only fair to do the same here- interestingly the Coffee Shop loo was nice and clean, whilst the restaurant was not so good!