We stayed at this small 11 room hotel twice January 2014. It is located in parts of the third and fifth floors of a large building near Republica. I believe they also have one or two apartments for rent on the fourth floor. There are several other small hotels in that same building. There is a guard in an office watching the door on weekdays. After dark and on weekends, the door to the building is locked and you buzz and identify yourself for the door to be unlocked. There is an elevator. You do have to walk up about five steps from the entrance to the elevator.
We found the hotel a delightful, relaxing place to stay. In particular, all of the staff were helpful, friendly and responsive. All areas of the hotel were imaculate. The bed was especially comfortable and our room facing the courtyard was quiet. The room was very nicely decorated and a very good size for a European hotel. Wi-Fi was available throughout the hotel, and the signal was strong. The hotel has a computer that guests can use in the breakfast room. There is very good light in the room. A hot water pot and tea and instant coffee are in each room. We did not use the fridge/minibar.
A large cold breakfast is self-serve. The staff prepare fresh coffee or cappuccino or hot water for tea on request. The breakfast includes juice, fresh fruit, yogurt, meat, cheese, cereal and milk, rolls, sweet pastries, and cookies. I controlled myself and did not eat any cookies for breakfast.
We liked the location near the Republica Metro stop. We walked to and from Termini several times. It was an easy ten-minute walk. There is also a taxi stand at Republica, and we used the cabs a few times when it was raining.
The staff brought breakfast to our room before our early morning departure. Although we walked from Termini when we arrived in Rome, we used the limousine service (a minivan) for our departing flight from FCO. Reliable and efficient.
We made our reservations online directly with Residenza Cellini. Communication was easy and clear. Off-season we paid a special rate, with an additional Rick Steves discount and a further discount for paying cash. Because we stayed for a week on our second stay, we were upgraded to the junior suite, a very large room.
I highly recommend Residenza Cellini. It was the perfect place for us.