I can't say enough positive things about this rental. Brand new, well designed, beautiful, comfortable. Responsive and friendly hosts, clear information, etc etc etc.
We stayed in another listing of Poly's just downstairs for a couple nights before moving to this one (simply due to availability) and Poly and her son in law Yannis made the transition super easy.
The location is ultra convenient to the beach, shops, and restaurants in Kamares but tucked away (literally across the bay) from the noise of the village and port. We recommend renting a car as a scooter can be a bit dodgy on the winding - and windy - roads of Sifnos. You need a vehicle to truly explore everything Sifnos has to offer.
I would not recommend this listing for mobility challenged people as there are lots of stairs outside and inside the apartment, but would very highly recommend it otherwise. Would instantly stay again if we ever make it back to Sifnos!