I had an extended stay at Josef's apartment.
As stated by others, the location of the apartment is surprisingly convenient. Right outside the door there are trams or buses to take you to Republic Square, Wenceslas Square, train station and more. Being at the base of Petrin Hill allows for easy access to green space. It's only a block away from the river and a slow-paced 20 minutes to Old Town Square.
Communication with Josef's team was fantastic: quick, attentive with a genuine air of hospitality. The apartment itself was fairly well equipped, though there was no oven or microwave (clear in the listing photos). The walls can be a little thin, but the complex does not seem to cater to "party clientele".
No question i would stay again and whole-heartedly recommend.