The Mariniana is a very comfortable, spacious place to stay, and it’s located very close to the Vatican, as well as some nice restaurants and a grocery store. The bed was extremely comfortable too, and the kitchen had everything I needed!
As other reviews have mentioned, there is a lot of noisy traffic (think ambulances, car horns), and when I visited in March, it was really cold and despite the radiators, it was still really chilly in the apartment.
However, I really loved the Mariniana, and it was in a part of town where I, as a woman traveling alone, still felt very safe! The SpaceIdeas staff was very responsive to my questions and made me feel welcome. I would definitely stay here again!