I had a fantastic stay at Robert and Pavel's place. The flat was clean and well-equipped, and they even provided a guide book for Prague that they made with tips on where to go and what to see. The flat was spacious and the balcony was a great feature. You can easily take the tram to central Prague/old district/clock tower, etc or it is easily walkable in about ~15 min - you miss the tourist crowds, but can easily get to the sites of Prague.