Overall, I give Theo's house a 5/5. A few comments as you consider staying here:
1) Host - Theo is amazing! He provided several recommendations for activities, dinner, groceries, coffee, and bakeries. Not to mention, when I checked in, he took the time to map out where all these locations were so I didn't get lost.
2) Location - the view from the studio is to die for! No view of the sunset but not that big of a deal from my perspective. I loved just sitting on the balcony relaxing - great for coffee & happy hour. The studio is down several flights of stairs - wouldn't recommend if you have mobility issues. The studio is located very conveniently off the main path in Oia. It takes ~10 mins to walk to any restaurant.
3) Studio - lovely studio. My usage of the studio was mainly for sleeping and it was perfect for that. I was a solo traveler but I think it could easily fit 2 - 3 people while still being comfortable.
4) Overall - amazing host, great location/studio & very happy with trip/AirBnb.