It is cheap to stay here, and the location is ok, everything you want to see in Florence is walkable. The breakfast is ok. But the decent things end there.
The main problems we had was the grumpy, mean and unfriendly attitude of Germain. He was ok up until we paid for all the nights we stayed. Christina at least tried to be nice. She did book us tickets to the Uffizi and helped us with getting around with a photocopied map of the area.
The shared bathroom is an issue. The noise from Germaine blasting the t.v. disrupted our sleep. He was just being grumpy and mean like we were not welcome there and we were nothing but polite and cordial to him and his wife. We were really respectful of them and their things. So we don't know why he liked to lash out at us, which made our stay terribly uncomfortable.
DO NOT STAY HERE IF YOU WANT TO BE TREATED NICELY

So the key thing is that Cristina and her family live at the hotel--the reception is their living room. You pretty much get your room to stay in. The breakfast is early and mediocre (but filling)--if you are like me, you feel a little sad having mediocre food in Italy. But if you just want a clean place to lay your head at night and get up and out early in the morning--no frills, but not dirty--Cristina House is the place is fine. Her guests are not the teeny boppers you find as you go towards the SMN station--but it is definitely not a relax in your room type place. They knock on your door at around 8:30 to deliver the mediocre breakfast, by 9 they want to clean your room...etc.

If you are travelers like us, you want to experience the real feel of the town or country you are visiting. Staying with a local family is a great way to do this. Christina and Germain were extremely hospitable and helpful. Their breakfast was bigger and better than most.. Also having breakfast in our room was a nice way to start the day. If you get a ride from the train station from Germain you get to experience the true Italian art of driving and what fun it was! The Chistina House was a great experience!

We met Germain (I think that was his name) at the train station and bartered a slightley lower price with him for a 3 night stay. He then drove us to the guest house (at this point we were slightely sceptical) we walked up the dark stairway to the Guest house and were very pleasantly surprised. Cristina and Germain were very welcoming and helpful, breakfast was fantastic, we found there was enought there to save 2 rolls each with cheese spread for our lunch which saved us an enormous amount of money!
There was a local information folder in the room which we found very helpful.
Location was fantastic although we did get lost on the way back to the train station (this was our own fault as Germain had provided us with a map and crossed the guesthouse, trainstation and town centre for us.)