To start from the end - I highly recommend this flat :) Sylvia and Martina were great - really helpful, provided a lot of information, very easy and quick to communicate.
The studio itself is what you see on the photos, the location is nice and while not central, it is right next to the Vatican and with a good transport link to the centre. Another benefit is its proximity in regards to a train station - very convenient from the airport.
The flat is also fully equipped, including the kitchen, which might be helpful for those planning longer stays. Overall, me and my girlfriend were very happy to stay in the flat and was definitely one of the best choices we have made on Airbnb.