Sandra's place is amazing. Location couldn't be better. 1 block from Ponte Vecchio means you have Florence right there.
The apartment is clean and confortable. We didn't use the extra bed or the sofa as we were just 2, but for us everything was great.
The only downside was the WIFI that didn't work. It took Sandra and Roberto a few days to come up with a plan B (mini router) that didn't work either. We understood the issue was not easy to solve, but when Roberto was looking for a missing router while we were at the apartment we didn't feel comfortable having him searching on drawers with our clothes in.
WIFI is crucial if you're in Florence as planning your days means a totally different experience than randomly walk the city.
Besides that, the apartment is perfect, clean and Sandra's been very responsive and took care of every detail. She even left my wife a birthday card and a present which was a very kind detail.
If we return to Florence we'll be back at Sandra's place (hopefully with internet issues solved).