We loved our stay at Maria and Stefano's. The apartment was just the way it looked in the pictures - clean, spacious enough, with everything you need for a comfortable stay (kitchen utensils etc.) and very artsy and unique.
Location is very convenient - just a few minutes from a metro stop that will take you to Vatican in 5 minutes and the city center in about 15. The neighborhood is rather quiet and calm but with everything you might ever need (shops, services etc.). Apartment also has a nice terrace to enjoy. The only little downsides during our stay was that wifi connection was rather weak (as we understood it was just a temporary problem and actually gave us an incentive to enjoy more of incredible Rome rather than staying at home, which turned out to be great) and that air in the apartment is a little bit damp (it is located in the first floor but overall did not cause any inconvenience to us).
Maria and Stefano were really good hosts, nice and helpful - thank you guys, much appreciated!:) Overall, we would definitely recommend this apartment for small groups of travelers who are looking for simple, yet pleasant and comfortable stay in Rome.