We've had a great stay at Maria's place. The flat is really spacious (much bigger than it looks on the photos) and well equipped. We've stayed for 6 nights and standard hotel room would get tight by that time, but here we've had as much space as needed. You can feel at home there.
The location is very good in walking distance from every worthy places in Prague - it takes approx 20 minutes of walk to get to Charles Bridge.
The staff at the reception was very nice and helpfull - especially Marysa. The parking spot, which was essential for us, was in a gate closed backyard.
If You hesitate on booking the place, I would totally reccomend!
Błażej