We never got to meet Valter, but his daughter Chiara was very sweet and helpful. She waited for us to arrive and showed us where to park (for free!). Then she gave us a map and explained the buses we should take in and out of the city center. Breakfast is included (coffee, juice, pastry) at the restaurant right downstairs and you get little paper vouchers to use there. They freshly squeezed the orange juice, which was delicious! There is also a good restaurant for dinner (la Vittoria) on the street below the apartment (good food and well priced). This apartment is very convenient if you are planning to spend a day visiting the Vatican (it's right across the street and when there's no mass, you can just walk right in through the columns). Getting into the city center takes a little patience as the buses are extremely hot and crowded.
The apartment itself was clean. The A/C works well, you just have to empty the water tank frequently. The shower head was my favorite part. The room we stayed in was not the one that I booked, but it was very similar. I would definitely stay here again!