Guido's apartment was great for our stay in Florence. Extremely close to the main train station (Santa Maria Novella) which made getting in and out of the city pretty easy. There are many shops and restaurants around the apartment, and it's a nice walk to pretty much any attractions. The AC was a welcome relief from the summer heat and the laundry machine also came in handy.
Guido was a great host and took the time to point out specific spots to hit in the city for food and drinks. Note that the apartment is on the third floor, so it is a bit of a climb if you have lots of luggage. Also, the apartment doesn't get a lot of natural light in the mornings, so be sure to set an alarm if you need to get up early!