We were very pleased with Ersi Villas. It's beautiful, clean, has a great swimming pool, and was very close to Firostefani, which I thought was one of my favourite towns in Santorini, as it was less touristy than the others. Santorini is quite a hilly island and so be prepared to climb stairs and steep inclines. It was a good workout for us. Elias was very helpful and gave us recommendations on where to go. And their breakfast was delicious.