Luisa really is a wonderful host! She gave such a comprehensive overview of things to do, see, and eat in Florence (and beyond). Many of Luisa's tips weren't things that I had read about, so I would have missed out on seeing many incredible things if she hadn't been so generous with her advice.
The apartment itself is great - spacious, clean, and well-equipped. (The only thing is that there's no washing machine, so for longer stays you will have to use a laundry). For us, the location was great. A very pleasant 10-minute walk to the main train station and about a 20-minute walk to the main centre. If you're planning to do day trips to places like Siena, Lucca, etc. it's great being so close to the station. There are also plenty of great shops/amenities less than 100 metres from the apartment (including a great local pizza place!).
Luisa is a wonderful host and I would absolutely stay at her apartment if I'm ever in Florence again!