Noisy, no internet, unresponsive host, no hot water. We did not have a good experience at Olga's. The location is close to the Duomo, but you can find a hotel with air conditioning and an elevator for the same rate we paid almost as close. If you've ever been to Florence, everything is pretty close.
It blew my mind that Olga did not respond to texts, Airbnb messages or knocks on her door. She obviously knew there was no internet (a recent review said the same thing) but chose not to deal with it or us in any way.
If you decide to book and need to open the windows, buy the wax earplugs. It is VERY noisy all night and day. And be prepared to lug your suitcases up to the apartment. It is on the second story but the floors are quite high. It was a struggle.
In fairness, we had hot water on day one but not day two. I wanted to leave after day one but my travel companion didn't want the hassle since we were only there two nights.
I honestly don't know how she is getting good reviews. I stay at many Airbnbs and this was one of the worst experiences.