I will keep it simple. If you are going to the Sydney Observatory this is a great spot. If you are going there with a family - I (as a Sydney local) would say it's the best spot to eat beforehand. Not only is it a great restaurant - but the steps to the observatory at 100 yards away.
The staff were wonderful. I was there with two dads and their children (3 and 4). White paper table cloths are an added benefit for kids to get creative pre-pasta/pizza. The staff were just chatty and fun and played with the kids.
Food is reasonably priced - value for money given its in the cbd. Food is flexible - have your pizza any way you like it. ask for a little more cheese on the pizza if you like that (as my friend did). The wine is reasonable too also. Loved the chianti.
If you are doing the observatory - perfect. I live in Sydney and there are many Italian restaurants. I would certainly come back. Service was great. Kids loved the place. And therefore so did I.