We had a nice stay at Maria's flat
It's really perfectly located, next to the Vatican, so you can enjoy all the main city monuments, and find nice places to have a drink or a nice meal
As I read the other comments before coming: yes, it's true, Rome is definitely a noisy city, and you won't find any accommodation perfectly quiet in the city center, BUT, just bring some earplugs as we did and you'll have a nice night I promise