Domus19 is without a doubt the best airbnb for young tourists, and anyone else for that matter. Fabio and Raimondo (the two brothers) are professional, friendly, welcoming and clearly experts in everything about visiting Florence and getting the most out of the visit. They told us how the city "worked" and gave us tips on where to stay and what to do, (and the best authentic bakery) which was perfect since visiting a city like this can be a bit challengin. There are so many more good thing to write about these hosts, but it's better to just expirience it for yourself ;)
The place was a nice reflection of the brothers and had the exact same great quality. It was very clean and closer to a hotel expirience, compared to someone's spare room. There were no second thoughts and we wish we had booked a longer stay there. We definitely will the next time we go to Florence.