This property is perfect in location, facilities, hospitality of the hosts and value-for-money. The rooftop terrace, to which you have access, gives a beautiful view of the cathedral. The rooms are clean and well-kept, basic in their decoration and ideal for guests who will spend most of their time out exploring the city.
It is easy to find, and can be reached on foot within 5 minutes of arriving at Santa Maria Novella station. Most importantly, rooms are fitted with good quality air conditioning which allowed me to sleep through the summer heat. Tina and Diego were polite, responsive and engaged at all times when I contacted them.
The only potential downside that I would point out is that the apartment is on the third floor, with (I believe) no elevator, so would not be suitable for guests with reduced mobility. Similarly, larger people may have trouble moving around in the bathroom as it is very narrow.