This was our favorite place to stay during our multi-week European vacation. Check-in couldn't be easier - Roberta and Stefano were waiting for us when we arrived. On top of that, they'd provided espresso and breakfast essentials for us to enjoy during our stay (which we did!)
The unit is very spacious and absolutely gorgeous - you feel like you are staying in a classy hotel but with all the amenities of home. By far the largest bathroom I've seen in Europe complete with a washer and full-size bathtub and shower. The kitchen and living spaces are all well-decorated, the bed comfortable, wi-fi reliable.
The location also couldn't be better. The Ponte Vecchio, Uffizi, and Palazzo Vecchio are only a 5-6 minute walk away. On top of that, Via dei Neri (right around the corner) is full of great gelateria, panini shops, and seems to have a fairly good nightlife - lots of young people drinking wine outside of sandwich shops, etc.
I highly recommend staying at Roberta and Stefano's flat when you're in Firenze. You will not regret it!