It is a great choice if you are looking for a spot that is a bit away from the most touristic parts of the city but still close to everything. It is located in a nice area with great cafés, restaurants, wine bars. Public transport is also available and it is worth to take some walks in the surroundings too.
The flat is cozy and comfortable for 2 people, it has everything you need for a few days. The view is really nice, the rooms are clean and well-equipped. The bed is narrow indeed (as other comments mentioned), but has a comfortable mattress.
Check-in and communication was super easy with the Prague Days team. I definitely recommend it, was a good experience.