My sister and I stayed at Guido's flat in the early spring. The location is as described, close to everything! We walked everywhere. I think the longest walk was to La Specola and that took roughly 15 minutes. Everything that you want to see and do in Florence is a quick and easy walk from this apartment.
The building is incredibly secure and we felt very safe returning late at night. The apartment itself has everything you need and is very clean. The kitchen and bathroom are both updated, but the vintage apartment holds lots of charm with large windows and pretty details. You definitely feel at home when you're staying here!
As our host, Guido was very accommodating. He met us at the apartment and carried our bags up the (many) stairs. After giving us a tour of the apartment, he gave us lots of local tips for things to do and places to eat. He went above and beyond our expectations as a host and helped my sister sort out retrieving her lost luggage.
We would both highly recommend staying here!