In one word: GREAT.
The stairwell is not the nicest i have ever seen, but do not get confused by that. The flat is just amazing, modern, comfy beds, fully equipped kitchen, nice bathroom with everything you might need and best of all the location. You cannot be more in the heart of the wonderful city of Prague.
Michal is an extremely nice host. He puts beer and supplies for your first breakfast in the fridge and was very helpful in preparing with the logistics. Unfortunately I could not meet him in person, because he was travelling. But he sent a friend (a very pleasant guy) of his to handover the keys and show the flat. All went very smoothly.

Thank you very much, Michal. We will definitely come again.