Susanna's place is stunning! I loved how big the room was and how accessible everything was in Florence. I lived in Florence a few years ago on the other side of the river but this place was in the heart right near the Duomo and it was perfect.
Great kitchen area, dining room, two bathrooms and plenty of space inside and outside the room to relax. The bed was fairly comfortable and I was able to walk everywhere easily. Totally safe area, too.
The only things I'd mention is that it does get loud at night sometimes if people are at the bars nearby, and there's a possibility you'll have roommates. Oddly though, I loved having roommates and met some great people that way. Everyone stuck to themselves, but also had good conversation when we crossed path or got dinner together.
Overall, I would go back and definitely recommend the stay!
(Oh! And the night I got there, I was an hour late with no way to contact them for check in, but they were extremely helpful and kind).