Family of four adults and one toddler had a great time. The cave is a little bigger than it looks in photos, and just as cool. Also, the multi-level balcony/porch offers that amazing view people go to Santorini for. Great mix of traditional and interesting cave with a functional kitchen and nice bathroom.
Extremely cool "architecture," amazing view, well maintained and reasonably close walk to whatever you might want. Note that stairs are a way of life on the caldera side of island, so you will be lugging up and down a few flights worth of stone steps. Worth it, but be prepared.
For those with a baby: nice crib was provided, but keep in mind there isn't really a separate room except the small bedroom in the back, which won't really fit the crib. It wasn't a big problem for us, but something to remember if you want to put the baby down but keep your own party going.
Yiannis and Kostas also offered great info on the island. Would stay here again.