I stayed at Costanza's place for around four months (February-June 2020). I got to know the apartment pretty well during that time and I can highly recommend it if you are visiting Florence. It's a truly beautiful apartment decorated with great taste and care. I should say that I found the apartment to be larger than it appears in the photographs, but everything else was exactly as advertised. There was a really lovely atmosphere and I felt at home from the day I arrived.
During the whole process of finding, booking, and traveling to the place Costanza was excellent and very prompt at answering my messages. She was extremely easy to deal with and answered any questions I had prior to booking.
The area around the apartment is very quiet, but the city center is just a short walk away (around 10 minutes to the Duomo), as is the main train station and all the main bus stops. There are a number of shops and supermarkets of various sizes within walking distance. Pharmacies, tobacconists, bakeries, wine shops, and convenience shops are all located within a 3 to 5 minute walk from the door. It really is the perfect base from which to explore one of the most beautiful cities in the world.
The apartment itself is well stocked with everything you might need during your stay. Wine, sweet things, and fresh fruit were left for me on my arrival. I cooked there everyday during my stay and there was never anything that I needed that wasn't in the kitchen. The bedroom is large with a very high ceiling and a comfortable bed along with plenty of storage space. Off the very comfortable living room is a little terrace where you can sit and have a glass of wine or just enjoy the Tuscan air.
The heating system in the apartment is automatic so you don't need to worry about it. When I arrived in February the weather was still a little chilly outside, but the apartment itself was never cold. Although the weather was rather warm at the end of my stay I never found the need to use the air-conditioning so I can't comment on that. By opening the living-room and hall windows during the day a wonderful breeze would blow through the place and at night I just used the fan that is in the small storeroom off the kitchen, which was perfectly adequate.
However, by far the best thing about this apartment are Costanza's parent's Alessandro and Roberta who live just next door. They greeted me on my arrival and answered any questions I had about the apartment and Florence in general. They really are two of the most wonderful people who you will ever meet in your life - always there to help without ever intruding. It was great to know that I could just ring the bell with any questions etc that I had. I really cannot praise these two enough.
All in all there is genuinely nothing negative that I can say about Costanza's place. I really do highly recommend it and when I return to Florence in the future I will certainly stay here again.