We had a really nice stay at Klaus apartment. He was very welcoming and friendly. The location of the apartment was good, only 15-20min walking through a nice park to the city center and even faster by tram, so a good location near the city center. Apartment itself was on the 6th floor with a nice view to Prague. It was also clean, comfortable and had all that is necessary.
I will highly recommend this apartment for your stay at Prague.