We stayed at the appartment for 4 nights and were very satisfied. The flat is very comfortable, with everything you need to have a good sleep, bath\shower and cooking food. Also it is really beautifully designed and suitable for 2 to 4 people (even 5 if you are OK with sleeping on a sofa).
It's important to say that the flat is on the 4th floor (that may be difficult for some people).
The neighborhood is clean and very quiet. The metro is about 3 minutes walk from the flat, and there's a tram stop very close too. So all the sights are accessible.
Marie and her family are very nice people, that were always ready to help with any question, answered all the masseges immediatly and were extremely hospitable.
Highly recommended,
Enjoy Prague :)