We enjoyed our stay in Polina's flat -- it is extremely well-located, in a less touristy part of Florence but still very close to all the major attractions. There are many great restaurants in the neighborhood and a self-service laundromat right next door to the flat. There is also a cafe right across the street whose pastries/espresso we enjoyed. Polina was a great host, very quick to respond and gave many helpful recommendations.
The flat itself was nice. The kitchen and bathroom have beautiful tiles, and it was very convenient to have a side door that exits directly into the street. I give 4/5 stars just because we found it a bit cold in December (there is a combined A/C-heater, but it mostly heats the loft, and not really the living area). Also, hot water is a bit limited, but this is not an issue for just one person/two people if they shower quickly.