Margherita's Airbnb is in a good location, about 10 minutes walk from Firenze Santa Maria Nouvella station. It is within easy walking distance of all the sights and - an added bonus - also near to the food hall above the main market (great for pizza, pasta, meat dishes, wines etc). It is decorated in a lovely modern style with lots of personal touches - much nicer than a hotel. We would not hesitate to recommend it.
There are perhaps two things to be careful about. First, the apartment is on a quiet street but there can be some traffic noise. I think this would be the same anywhere in Florence and Margherita's thick curtains and shutters certainly help. But light sleepers might want to bring some ear plugs. Second, we were asked to pay an unexpected cleaning fee on departure (which we refused to pay because it was not included in the Airbnb price). I understand Margherita will include the fee in the main price from now on.