This is where you want to stay in Prague. Not only is the apartment / loft stunning, with heigh ceilings and grand old windows, the location is also superb. I always prefer Vinohrady over the city centre because it's not as crowded and I love the architecture. The apartment is really close to Namesti Miru and Muzeum, so you have great access to the metro.
Jaroslav was really quick in answering our requsets and really helped us out when we had to stay two more nights because our flight was cancelled.
Highly recommended!