The flat is perfectly located in the center of Prague. I arrived in the morning with the Airport Express bus (no need to use taxis), and Petra was waiting for me in the flat. She was very nice and helpful, and the place was very clean and fully equipped for a week's stay. There is a nice kitchen which we used several times for cooking, although you don't really need to in Prague.
The internet connection was working well, except for one time - and Petra was very fast to fix it.
My only reservation is that the bathroom is not inside the flat, but next door to it. This would be a non-issue if it wasn't cold outside. Overall, this flat is warmly recommended.