My wife and 3 girls (ages 11, 9 and 6) stayed at Volker's place in February. As many of his previous guests have commented, overall it was a fantastic experience.
The location is great...while the neighborhood is a bit busy the penthouse set-up felt like an urban oasis, with great views, plants all around and decent noise proofing. From the deck you can even catch a glimpse of the harbor bridge and Opera House! We were able to walk to the Royal Botanical Gardens and Circular Quay (~ 25 min) and the lovely Hyde Park is 4 blocks away. Also tons of great restaurants and a high end grocer...
The amenities were top notch...high quality bath & beauty products (which my wife loved in particular), great mattresses, high-end appliances, as well as personal touches like fresh flowers and fruit upon our arrival.
Volker is a great host...super responsive, friendly and has great energy. We truly enjoyed our stay!