The Semelli cave house is an amazing space. Travelers should be aware that there are quite a few steps to get in and out so plan accordingly with luggage. Also, as it is a cave house one room leads to the next, so in order to get to the bedroom with the double bed, you must travel through the room with two singles. (This annoyed my daughters but was really fine!)
Vaggelis and his staff were AMAZING and the daily housekeeping is a big perk. The hot tub is a super nice amenity.
Exo Gonia is quiet but with a rental car you can really travel all around the island quite easily. The best taverna on the island, Metaxi Mas is a short walk from the villa.
Do not hesitate to book at Semelli Cave House. You will NOT be disappointed.