Like with anything else in the world, there are really good dog daycares in Sydney, but also some bad ones. I recommend visiting a few and finding the one that you feel most comfortable with.
The facility should be clean and look like a safe environment to leave your best friend.
Pay less attention to the aesthetics and more on the space safety. I actually prefer less stuff in the play areas. I like just a simple room with some toys and few obstacles. I think simple is better for the play areas.
Although an outdoor area is nice, it would be very difficult to find a place with outside area in the city.
The most important thing to focus on when you’re picking a good dog daycare in Sydney is the staff. Are they friendly and professional? A good daycare will also be honest with you and tell you when something has happened or if your dog was a jerk that day. Believe me, dogs aren’t always having a good day either.