My friends and I stayed at Casa Ventura while we were in Florence for a wedding and it was such a wonderful experience!
Karin is a gracious host, was quick to respond, and maintains a beautiful home. The location is perfect and convenient to all Florence sights. The apartment has all the amenities you need and more, including hairdryers, an iron, automatic blackout shades and three terraces.
Definitely stay here during your trip, it's better than a hotel!