I stayed at Giovambattista's place for 2 nights, with my girlfriend. And we were delighted!
He welcomed us on time, by explaining all we had to know about the flat in 2minutes, we didn't have anything more to ask. Giovambattista is a true artist, he's always doing something, but still very easy going. He'd helped us, giving us tips on restaurants for example. We really enjoyed talking to him, and had fun together after a few minutes only. He's a great host! And if you're lucky, you might see the master at work ;-)
His flat is simply AMAZING. It's a museum on its own. The room is probably as cosy and beautiful as it is remarkable : a lot.
Finally, a few words about the location : it's easy to find, in a lovely and lively (but not annoying) area, with good restaurants around. It's less than 10min walking away from Ponte Vecchio, and it's 15min max walking from the main train station, which makes it very convenient.