My family and I stayed for two nights in L'Aranceto Guest House and it was a great experience. Domenico was very friendly and was prone to help us in whatever thing we needed to.
The room looked like in the pictures and it was very clean and comfortable. The bathroom was good and very clean. Having the kitchen available to cook was a plus since we could cook our meals if we wanted to. The only thing is that since you share the fridge you should be careful to mark your stuff so other people would not accidentally grab it.
The area around the guest house was safe and well communicated with Stazione Santa Maria Novella and the city center through various bus lines. However if you plan to come back after midnight, there isn't a "nocturne bus line" so you will have to take a taxi.
We loved our stay here and we would come back, I would also recommend it to other people.