This is a truly unique apartment, it feels like you're staying in a museum or a palace. Location is just perfect - in 10 minutes walk from SM Novella train station and bus station and all touristic attractions. Kitchen is well-equipped. The apartment looks very "antique" but was also clean and seems like the renovation was rather recent. The only downside was it's uncomfortable for two or three people to use showers/wash up at the same time in different bathrooms (for example, in the morning), because the building's communications just can't handle it. But it's a problem with all historic buildings in Florence. Also a friendly suggestion for the host - it's rather challenging to figure out which switch turns on the lights in certain places, so maybe it would be helpful to make little signs under switches. And it would be helpful to have a "house manual" printed (like, how to sort the garbage, where to find the iron, hairdryer, adapters etc, maybe some information about the collection of antiques and paintings in the apartment).
So, I would definitely recommend staying in Federico's apartment and feel the artistic atmosphere.