This isn't really a negative, but I would forewarn that the door/lock to this unit just needs a little wriggling to get open. Don't worry, its not broken and you're not locked out! One downside was that they didn't have a card reader for payment w/ Visa. It did make me nervous to withdraw that many Euros and walk around, however the SILVER LINING of this is that the ATM is extremely close, located in the new upstairs food court of the Mercato Centrale. Therefore, there wasn't a long walk back with all that cash, which you always have to look out for.
I personally stayed in a triple/apartment style unit, which was actually located ACROSS from the main building of the B&B. My train did not arrive until later, so I did have to wait 20 minutes for her to arrive back to drop off keys, but that was ok. If I come back to Florence, no wait - WHEN I come back to Florence I will definitely want to stay here, in this unit. It was lovely and very modern and chic! Of the many many hotels, b&b's and boutique places I researched, they were very expensive and the rooms looked like the left little to be desired. The place seemed totally renovated, and had a perfect little kitchenette with all appliances hidden by modern cabinet doors. I wished I had been there longer and/or had others with me, because it was fully stocked with everything you'd need to cook wonderful meals at home. Pair that with the great location in the heart of San Lorenzo and the Mercato Centrale, everything you'd need to make delicious food was literally at your fingertips! I was pretty sad that I didn't have time to actually cook a meal (or really have anyone to serve it to, ha) because it would have been perfect. The living room had a pull out futon and another twin size bed, which in addition to a large bed in the bedroom - this place would fit quite a few people! WiFi was available and worked, but only in a specific spot by one window, however there was a bed there and it made an absolutely fine place to lounge after a long day and go online. Daniela was very responsive to emails and questions, and I enjoyed meeting her! Stay here!