I stayed at Enrica's appartment for 4 and half weeks in January/February 2023, and I had the best time.
The location is great, the main tourist attractions are on the other side of the Arno, but make sure you also spend some time in the appartment's neighbourhood, because there are plenty of nice restaurants and gems, (and, in my experience, less tourists). Enrica can recommend you some trattorias with great, local Tuscan food.
Enrica is a wonderful host! Very kind, very responsive. I took some Italian classes from her, which I recommend! She adjusted them to my level, it was very nice.
To give you an indication about the gas/water/electricity bills: I paid 70 euros in total, for 4,5 weeks during winter time. I'm a pretty conscious consumer, so I kept the heater off most of the time (since I was outside a lot anyway).
The only negative I can think of is that the wifi isn't perfectly stable. Sometimes it wouldn't work for a couple of hours. When it does work, it's great.