Karin's apartment is simply wonderful! My boyfriend and I spent 3 nights there and it had everything we needed for our stay in Florence, and we wished we could've stayed longer because it really felt like home. The location is superb, very close to all the main points in the city, 5 mins walk away from the cathedral and the river, and has a few supermarkets close by as well.
Karin is a lovely woman, she helped us to organise a walking tour around Florence and gave us recommendations for places to eat and have gelato! She also allowed us to leave our bags in the apartment even though we arrived before the check-in time, which was a very kind of her.
The only "but" that I would like to mention is that the street where the apartment is located is quite noisy; the restaurants receive their delivery at around 6 am, so don't bother to set an alarm because the lorries will wake you up!
Apart from that small detail, everything else was perfect. We can't wait to go back!