Hard to review this hotel.
We have been to Rome several times in the past, so we knew the location very well, and that was the reason we selected this hotel.
We stayed in the suite in the annex portion of the hotel, room 311.
The location is great, right on Piazza Rotunda, you can easily walk to any attraction in the city. From the hotel, it's about 35 minute walk to the Coliseum or Vatican, and 20 minutes to Piazza di Spagna - 3 locations on completely opposite ends of the historical center. All the other attractions are within this triangle - so you are close to everything.
The suite is very large - more than adequate for 2 people, would be fine for 3 (daybed in sitting area). Opens directly onto the plaza, with great great view of the Pantheon.
The staff was friendly and accommodating (checked us in before 12 while their policy was 2 pm).
These are the best qualities of this hotel. It definitely is not what I would expect a suite in a 4 star hotel to be like. The room, though very spacious, lacked any character, was very sparsely decorated, and had a miniature bathroom (turning around in it one had to be careful not to knock off toiletries). The view was great, but we kept our drapes and shutters closed because it was very noisy. The breakfast was adequate, but not extensive or particularly tasty. The location was very convenient, but there are dozens of other hotels in a 3 block radius.
We have stayed in many small hotels around Europe and knew what to expect. A 4 star rating is far too generous. Consider it a small, clean, well-run, centrally located 3 star, and compare it against others in the same category. The hotel needs to either drop a star from its rating to reflect the level of accommodations, or do some serious renovations.
That being said, I feed I shouldn't be complaining because at the end of the day, I paid 175 euros/night, inc. breakfast, for a huge suite overlooking the Pantheon. Even though the room and the hotel was not what I would expect from a 4 star, neither was the price.
The room was noisy, but you can't have both a quiet stay and a view of the prettiest and busiest square in Rome. I am sure other rooms very quieter.
So, even though I have serious reservations about staying in this hotel again, I did get great bang for the buck. Had the hotel been rated a 3 star as it deserves, I think my expectations would have been met. Book it if you get a good deal on it.