We can only recommend this apartment!
It's very close to the city centre and you can get everywhere by foot. There is also a map, which is marked with every important location close to the apartment (supermarkets, restaurants, exchange station). The apartment is way bigger than expected! Very friendly hosts. They were easy to communicate to and always available. All in all a very good experience in Prague and we enjoyed our stay to its fullest. Will definitely come back here again, if we're visiting Prague :)