We loved our stay at Korina and Katerina's. The apartment was designed simply and tastefully and had a terrific terrasse with a stunning view of the sea and a small beach. Although windy, we preferred this less touristy side of the island where the beaches are less busy, prettier and have sand. Katerina was very welcoming and suggested a few good restaurants.
The beach below Aspes was our favorite as well as the taverna where the waiters were low key and smiling.
Serifos is definitively one of our favorite island.