Our stay at Caterina was very pleasant!
The apartment was just the right size (we were three people, but you could easily be four), and located in a central area with amenities right by. Just a few steps outside the door you find a great gelato shop (which we believe is the best we tried in Florence), pizza place, small shops etc. Very close to the Palazzo Pitti, and just over the bridge you find the Uffizi gallery and The Duomo.
Check in (and check out) was very easy and Caterina took her time answering questions and giving small tips only a local would know. She was very welcoming and cheerful, and just a message away.
If you are a light sleeper you might be disturbed by the lively city outside, but we found it to be charming. There is no AC, but if you keep the windows and shutters closed throughout the warmest parts of the day it shouldn't be a problem. But maybe avoid opening windows at night, as there are mosquitoes.