I've been to Posto Pubblico three times now - twice for dinner and once for lunch (the photos below are from lunch). I thoroughly enjoyed my first two visits during dinner; not so much my most recent visit during lunch.
During my first two visits, the caprese salad was amazingly fresh and delicious, the antipasti platter was sublime and the pastas perfectly al dente. I don't know if they use a different chef at lunch, but the quality of the food was completely different. The mozzarella was tough and bland, the pasta was overly salty. And in my opinion, the lunch sets are overpriced for what they give you, and there are too many exceptions to the listed lunch set price - for example, if you order any of their special pastas of the day, you have to pay an "upgrade" price to the more expensive lunch set price of 180 HKD instead of 120 HKD.
There are better Italian restaurants in Hong Kong (my favorite so far is Pane Vino on Mosque Junction Road), but in my view, a visit to Posto Pubblico is still worth it for their fresh house-made mozzarella.
Caprese salad made with fresh house-made hand-pulled mozzarella (the primary reason I am a fan of Posto Pubblico)
Brooklyn Special sandwich (breaded eggplant, mozzarella and roasted peppers)
Tagliolini with peas and pancetta
Food rating: *** and a half
Bang for buck rating: 3
Location: 28 Elgin Street, Central, Hong Kong
Average price of dinner for two: HKD$700 (~ USD$ 90)