I really loved the stay in this place, the apartment is excellent for groups of 3 people - there are two rooms inside so it gives privacy. The main bedroom however does not have a door - so keep it in mind (but IMO it does not make any trouble) :)
Regarding localisation - it is perfect, especially if you want to visit the Vatican (only 10 minutes away!!!). Just beneath the tenement, there is a metro line A so any further destinations are easy to reach as well. There are a lot of small restaurants around and delicious pizza sold on slices is just around the corner.
From disadvantages - the apartment is pretty humid (water condensates on windows through the night) but the weather, in general, could have caused it. Breakfast is in price, but remember it's Italian style (so only croissant + coffee) and count about 20 minutes for it due to the service.
In summary - highly recommend it, would stay here again! <3