Location, location, location! Convenient to all the places we wanted to visit in Prague, but in a quiet area without tons of traffic and noise. We pretty much walked everywhere, but public transport is really available in the area.
The building was secure and well maintained, and the apartment was immaculate. Had everything we needed. It was a very comfortable space to relax in after a busy day off sightseeing.
Host responsive and available but not at all intrusive.
Highly recommend.