We stayed here after reading the TA forums and the website of the Casa as there were no reviews. We stayed in the studio.
We are glad we took the punt based on no reviews. Maria is very helpful on the phone when booking and can arrange hire cars, transfers, etc or just provide directions.
When we arrived (by hire car, which we recommend) we called Maria and within 5 minutes the extremely friendly and fun Vassilis arrived to help us with our bags (and I mean help, he carried both our 20kg cases all the way to the Casa. This guy deserves a medal). He also gave us a couple of good tips for tavernas and places to see.
The Casa is located about 30/40 steps or so down from the main path of Oia. Its cut into the rock face. Its not too strenuous a walk (Vassilis takes the bags anyway) and is fine for anyone of middle fitness. I would avoid it if you are disabled or extremely unfit (although to be honest, avoid Oia totally if that's the case). Its about 3 minute walk to the main square and the same to the castle (its located halfway between the two, down the hill).
The Casa itself is very pretty. The view is spectacular and the little veranda has a table and couple of chairs to sit and read / drink wine etc. You can't see the sunset from here (as with anywhere on this side of Oia), but its only 2 minutes to the castle so don't worry about that.
The Casa has a little kitchen, although we didn't use it so can't comment. It has a microwave / grill and little hob and a fridge (which we did use). It also has its own private shower room. The only down side of this is that the hot water tank is small (20 litres). That means about 5 minutes of showering before a reheat is needed (which takes 20 minutes) but the shower is big enough for two people unlike most Greek showers.
Overall this place is extremely romantic, very private and tucked away. The price is good for Oia and we would definitely stay again. We stayed mid-May and it was pleasant, although I don't think there's air conditioning so it might get hot in summer. There is a fly screen door, so you could leave the door open no problem (its totally private and safe, so no need to worry about this).
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.