We stayed in Oliver's apartment for 4 nights in January. Oliver was incredibly responsive, answering questions within a few minutes of emailing. He was also very flexible on check-in and check-out timing.
The apartment itself is great value with 2 bathrooms, 3 bedrooms, a stylish living room, and a kitchen. The furniture & amenities are a little on the older side, which was fine with us! It's a charming apartment that easily fits 5 and probably up to 7 people relatively comfortably. We also liked that we were very close to the Palermo bar scene (maybe a ~5-10 minute walk).