Monika's place is WONDERFUL. A few notes for check-in: when she describes it as a "tower," it's literally that. From the outside it looks like a medieval tower (made of bricks, with ivy growing on the outside. This is where Rapunzel probably grew up.) So don't look for a modern apartment building on the outside. Also, what the Italians call the "second floor" is what Americans would count as the third floor--so note you'll need to go up one extra flight of stairs to find the right door.
The space is definitely cozy--but it's the perfect size for one person. Enough space not to feel cramped (and you shouldn't spend too much time indoors anyways--you're in Florence! Go walk about this amazing Renaissance city!) There are so many great places to eat (restaurants, caffes, gelato shops) within a 10 min walk (really, within 5 minutes or less!), so eating is very convenient. It's also SUPER close to the Arno and Ponte Vecchio, which puts it near a great part of the city. (The Uffizi is very close, as is Piazza della Signoria. My favorite thing was to walk up to the Piazza Michelangelo (I did it twice a day!) It's about a 20-30 min walk, but you'll get a breathtaking view of Florence. If you're just one traveler, Monika's place is an amazing place to stay.