I had a fantastic stay at Mario's flat. The flat has a perfect location for exploring Florence and is extremely convenient to the main train station. Mario was a great host from start to finish - he responded very quickly to all of my messages and went out of his way to assist me throughout the stay - he really does do anything he can to help his guests have a great stay.
The apartment is as good or better than advertised - very large, clean and comfortable, and has everything you need for the stay. The neighbourhood is good - there are restaurants nearby as well as a great takeaway pizza place just near the apartment, and is within a couple mins walking from either the river or the Santa Maria Novella train station - ie, a perfect location for a visit to Florence, including if you plan to make any day trips by train (eg, I went to Arezzo, Pisa and Lucca), so it was great having the train station so close.
Mario want above and beyond, and even left a great dessert made by his wife as a welcome present, which was perfect after my tiring, early flight.
Overall, a fantastic apartment and host, and I look forward to staying again when I am next in Florence. Thanks Mario!