We felt very welcome in Barbara's flat, she is very friendly and took time to explain how everything works in the apartment and gave us useful advise on what to visit and where to eat nearby!
The flat itself is quite large, it would suit groups of up to 3-4 people, although we found it dark because of the ground floor location and small windows. Don't expect luxury, it's functional furniture and ok decor. We were struggling to get in and out due to the number of locks and the quirkiness of those, but after a day it gets easier. As a base for exploring the city it would work very well! The building itself is very old and characterful.
Neighbourhood is lovely and central. Everywhere in the historic centre is reachable by foot no problem, Ponte Vecchio is very-very close as well. We felt very safe there. The only thing to note (for light sleepers) is in the early hours the nearby bars close and everyone starts heading home and you can hear it if you sleep in the bedroom, but the living room gets no noise from outside at all.