We loved staying in Peter’s apartment. It was clean, spacious, comfortable, and quiet. It was just a few minutes walk from the opera house and we could easily get anywhere inside the Ringstraße from there. It is approximately a block from Karlskirche and Karlsplatz (excellent transit options at Karlsplatz). The neighborhood felt very safe and we walked at all hours with no problem. If we go to Vienna, we will book with Peter.