This flat is in a perfect location. Literally 3 mins walk to Piazza Narvona. We could easily walk to the Vatican and Bridge of Angels, Campo de’ Fiori. There were lovely restaurants locally, I would recommend, Il Corallo restaurant just passed Da Francesco restaurant.
Although we could hear slight noise from the bar opposite it didn't bother us, nor did the climbing stairs, but as Simona states there is no lift.
Both beds (including sofa bed) were very comfy. We had to put the air con on one night and it seemed to be working.
Sightseeing tip: when visiting the Vatican take some time out to have a glass of prosecco and a beer in the courtyard restaurant. Was pleasantly surprised at the price and quality.