We really enjoyed our stay in this flat. The apartment was clean and well equiped. The 24/7 reception was definitely a plus for whatever we could need, the people were really helpful whenever we had a question. Moreover the apartment is ideally located in the middle of the old town, everything is nearby and we didn't need to use public transport at all during our trip, except to go to the airport. The building itself is beautiful, with a very high ceiling, the only less "ideal" point would be the noise: from inside the flat, we could hear everything from the corridor and the people walking in the apartment above (but no noise from the street, it was very quiet). Still, it didn't bother us really as the point was not to spend the day in bed but to visit the city :).
We would recommend this apartment with no hesitation and certainly go there again for another trip in Prague!