Wow... what a great find! I had business in Sydney for 3 weeks and brought my wife and adult daughter along. Manly made a great launch point for all our excursions. For business, I was able to hop the Fast Ferry and be at my CBD office in about the same time it would have taken to get there from any hotel. As a bonus, I had a chance to enjoy a beer and unwind on my way back each evening.
Manly has several great restaurants and coffee shops, with a good sized grocery store nearby. Given the expense of eating out in Sydney, this saved us a bundle on breakfasts and some evening meals. The apartment was well equipped for cooking, though I would have liked them to stock some spices and such.
The only caveat is that the unit is at the top of a significant hill one must walk up from the wharf. There is a local bus, but it doesn't run frequently. Uber took us up during a rain storm - $8, so a good option in a pinch. But between that and the stair access, I wouldn't recommend this for anyone with mobility issues.
Bottom line... I hope to rent this unit again for my future visits.