My wife and I recently returned from a weekend away staying in this apartment and I can't recommend it highly enough. Your a few minutes walk from all of Pragues attractions and sights as well as local bars and restaurants.
The apartment was a little smaller than I thought it was going to be, but perfectly adequate for the two of us.
JJ was very thorough in his communication, always staying in touch, and organised a taxi to meet us from the airport and bring us to the apartment which we thought was very nice of him.
If you decide to stay here then you won't be disappointed, although a word of warning that if you need to buy a few bits (water, milk, bread etc) then do not use the local mini markets. They are extremely overpriced. If you goggle map "my Tesco", then you'll find all you need in a supermarket that is 1/4 of a price and is only 5 minutes walk away.