The flat is very beautiful and spacious, which we really liked.
I wouldn't recommend staying there if you plan on visiting the city and get a good night rest, as the neighbourhood is very noisy (drunk people from the bars nearby screaming and fighting in the street at all times of the night) as well as the neighbours in the building (30 people party until 4-5 am, super loud music on Sundays at 10pm...the walls of the flat were trembling!). Plus, the curtains are thin, so you are awaken early by the sunshine.
It is a great flat if you come to party in Prague all night long, but not if you want to have a nice rest after full days of sightseeing.