Hata is a very kind host. She did all she could to make my staying as comfortable as possible. The house is exactly as in the pictrures and in a perfect location, between Mala Strana and Kampa. This means that it is downtown but on the quiter side of the river (no noisy tourists...).
A few tram lines nearby allow you to reach other parts of the city quite efficiently.
The sleeping room is definitley large with a single bad and a double one (but not queen size, it is a bit narrow for two people). A kitchen and a small dining room are available. The kitchen is small and "minimalist" but there is all you need to cook for a couple of persons (no oven). The small bathroom beside the kitchen is shared with Hata.
Nearby you can find several nice restaurants and bars. A large shopping centre and supermarket is 4 stop away by tram (but you can find smaller ones at walking distance).
I definitely recommend this apartment, I've stayed over a month and I have nothing to complain about.