Contrary to some past reviews, the communication was not too efficient with my experience. Had messaged the owners for confirmation of the stay as well as an alteration of guests weeks prior to our stay. However, the only message received was in regards to check-in the night before. During the stay, I had also asked questions about the Wifi which was left unresponded. This was fine since the stay was only one night but would have been problematic if it was longer.
In terms of the place itself, we stayed on the 48th floor in room 4808 with great views of the city in a perfect location in Melbourne CBD. However, it was not a "penthouse" as avertised and also no adequate sleeping arrangements for 6 people, only two double beds (though this might be different if you let the owners know you have more than 4 people staying). Some issues with the bathrooms like no bins and the door not shutting properly, but these were minor issues.
I think if you're looking for a place in the CBD with amazing views, this is the perfect stay. The place is a lot smaller than it is advertised and would not recommend more than 4 guests.