This is a great place to stay in Florence, it's a five minute walk from the train station and walking distance to everything else you'd want. The apartment is well organised, clean, and everything worked. I didn't meet Niccolo but his friend Simone met me at the apartment and Niccolo was available by phone.
The walls to the other apartments are quite thin so you can hear when the neighbours play music, talk etc. but there was never any noise at all during the evening so it wasn't a problem.
I can definitely recommend staying here.