Matt send us some very useful information material before our stay (with maps, recommendations for pubs/restaurants, some basic words in Czech language etc).
We met him twice, first when hand-over they keys, second accidentally at the tram station, each time he was very kind and friendly!
The flat was perfect: enough space, clean, comfortable, well furnished (only a hairdryer is missing)
By foot it's about 15-20 minutes to center, by tram it's about 10 minutes to Wenceslas Square; the tram station is very close to the flat.
I highly recommend this flat!