We (couple, m26 and f28) spent three nights at Valentina's place during Easter.
Overall our experience was great!!! The apartment is located in a nice and quiet neighborhood and extremely well connected to the city center - one of the city's very few tram lines is just nect door and takes you to Trastevere (20 mins) and P.za Venezia (25 mins). It is much bigger, much cleaner and much nicer than one might expect from the pictures!
Valentina was very nice and helpful. She welcomed us with coffee and sweets, offered tips and suggestions on where to go and what to visit, and stored our luggage after checkout (which helped us a lot!!!).
We definitely recommend staying at Valentina's place, and look forward to doing it again on our next trip to Rome! :)