We stayed at the Frattina 57 for 2 nights (we actually stayed in the other building they have 2 streets away) and enjoyed it overall, but there are a few little things that would need to be improved, for instance: the breakfast, which was Italian (an orange juice, tea or coffee and a pastry taken at the small bar at the corner), was honestly not filling enough, even for those who don't eat much in the morning. Bottled water could also be provided on a daily complimentary basis, again given the standard of the property. One last note, in our bedroom, the water/waste pipe was right behind the bed, making having a peaceful/restful night absolutely impossible, it just seems like a fountain run behind said bed, but the other room was not affected by such noise.
This being said, we enjoyed our stay thoroughly, we were warmly welcome by Dorota upon arrival and both our rooms were ready before check-in time, which is quite unusual for hotels. The rooms are quite big and very well appointed, the beds are comfortable, and the staff at Frattina 57 is more than helpful and available. The location is absolutely perfect, and I highly recommend this property.