We stayed 3 nights at Guido's apartment and we had a great time, as mentioned before, the location is superb, the apartment is well equipped and Guido is a wonderful host, he was very attentive to our every need, always available and attentive. My wife and I stayed there with our 1.5 years old baby and even though the apartment is not big it was very comfortable.
Some points to notice, first, the noise, this being the city center and all, even though the apartment is on the 4th floor, there is still considerable noise. The second point is the road work being done in the street and is set to continue until the beginning of April, the access to the street and the building, at the time we were there was obstructed and since it was raining and we had a stroller it was inconvenient. I still recommend this apartment but this is something to be aware of.