I would certainly recommend Casa Guido to anyone visiting Florence.
Lorella was an excellent host. She answered any questions I had about the apartment very quickly, and even sent videos and pictures to show us ahead of time how to get access the lock box and open all the doors. We didn’t get in until midnight, so having the lock box and all the information before we flew was extremely useful.
The apartment itself is really centrally located, and all of yet main attractions are a 5 minute or less walk from the apartment. I thought it was even nicer than it looked in the pictures. Lorella has left a couple of breakfast treats, coffee, milk and a bottle of Chianti as an added touch. The bed is extremely comfortable, and we used the little private terrace a lot.
I would say that if you don’t like stairs, there’s a fair amount. And the street sound does carry up, but the street isn’t a main one and was woken up by any noises during the night.
Overall, if I come to again I would certainly check first if Casa Guido is available first.