We stayed at Palace Santo Spirito for a full month in the heat of August, and it was wonderful! Here's everything you need to know:
1. The location is ideal: right on the piazza where young people gather every night. We had our 20-year-old daughter with us and wanted her to enjoy herself and not worry about her getting home every night -- this worked perfectly: we could see her from our windows and feel comfortable. We also found we went down nearly every night for a glass of wine or a Spritz and absorbed the atmosphere, and then our 10-year-old could could easily come find us. The Piazza is poppin' but it's less touristy and less packed than the rest of Old Florence areas. It's all about the nightlife here and there were concerts on the steps of the church on the weekends, which you can easily see and hear from the windows! On that note, the front two bedrooms do hear the noise all night long (it usually quiets around 2-3a -- I listened to sleep music through AirPods to drown it out); the third back bedroom with the twin beds doesn't hear this noise, although the child who lives downstairs is fairly loud while he plays during the day so this isn't the ideal room for the person who sleeps in.
2. The layout is perfect: the bedrooms offer plenty of privacy and are really large, with a few sleeping configurations if you get more guests. The bathrooms are well spaced out, and really offers great space and comfort so no one feels on top of each other. It was great for our family, but I imagine also great for individuals traveling together. Also, a washing machine, dishwasher, large refrigerator, and plenty of dishes to use. Everything is really clean, too. And, being there for so long, they did give us clean towels halfway through our stay upon request, which we appreciated (because there's no clothes dryer, we learned towels dry really stiffly).
3. The A/C is strong, but be aware: the units are only in the bedrooms, so the main living area doesn't have air conditioning (we bought and left a fan, which helped a lot, and as this area has no windows, it manages to keep cool). However, the kitchen and back bath get really hot, at least in August, so we mostly didn't go there (doors close it off, so as to keep the rest of the area cool. And, because of the mosquitoes, you don't necessarily want to leave the doors open.
4. Mosquitoes aren't really a problem for this flat. I'd worried after reading someone else's review, but don't worry. We found when we arrived in the last week of July, there wasn't a mosquito issue (and one of the hosts told us the Piazza Santo Spirito area had been treated to minimize). One week in mid August, the mosquitoes were bad in the area - so we stopped opening the windows. There are mosquito vapes, we just had to replace the pots and wore bug spray when we went out, and it was fine.
5. We did have WiFi issues, and Federico tried to work with us to solve it. We had to work and with no TV in the place, we had 3 adults and a kid reliant on WiFi for Zoom, streaming, etc. It was a problem. Federico got us a mobile device, and it was helpful, but didn't solve the problem. For most people, the WiFi will be fine. And, we had some friends who traveled through Florence while we were there, and they said they had similar WiFi issues where they were staying, so it could be the providers there. We would occasionally go to Caffe Richi across the piazza and get a spritz and use their WiFi when we had issues -- not the worst thing in the world:)
6. The only real complaint I have about the space is that all that beautiful antique furniture isn't particularly comfortable, and it's the only reason I'm rating this place slightly down. The master bedroom bed was broken and the bed sloped downward so we found two people couldn't sleep in it comfortably; the springs in the red love seat were also broken and it's not really something you can sit on for more than a few minutes. Several of the other chairs were broken or near breaking. We did ask Federico if he could bring us one comfortable chair, and he wasn't able to do that. But, now that we've made them aware of the issue, hopefully the flat owner will replace. We found the dining room table was the best place to work, and the back bedroom table and chairs were pretty good, too.
Overall, Federico is an excellent host and the flat offers a lot of advantages you just can't find in other places.