The apartment was indeed very cozy and had a great atmosphere. Everything was as advertised (in text as well as on the pictures). Ondrej was a very helpful host and although we did not meet him, he gave his best to arrange us the keys.
What I would like to point out specially, is that the studio is located in a very nice and quiet neighbourhood and thus is a great place to stay for those, who would like to see not only Prague's tourist attractions but the city's vibe in not-touristy places. We took walks to adjacent parts of the city, which were also beautiful and had some nice pubs, kafes etc without the crowdiness- so I would highly recommend that. But, of course the apartment is also conveniently connected to the centre and also to airport by means of public transport, so as it may seem to be a bit far on the map, it is really no problem at all.
I think it's already pretty clear, that we were very satisfied with the apartment, but it's clearly not for everyone. It should be born in mind that it is small and also not for those, who like extreme cleanliness (was a bit dusty, but it didn't bother us).
All in all, we enjoyed our stay very much and would definitley consider staying there again, when in Prague.