Apart of excellent coverage of destination within China, CZ also has a good coverage of Central Asia destinations. OneWorld lacks airline that serves Central Asia destinations and so the alliance might see this as a value of CZ.
CZ J class service on long haul has improved greatly over the last 3 years. Better champagne, white wine is cooled, better food is served and more crew members speak English. Oh, and they serve drinks from the bottle they bring to show the customer. They roster one crew member from the country the flight originates from or lands in, e.g. Dutch, French, Australian staff member that was on my flights. If the crew finds it hard to understand what the customer wants this expatriate crew member is called in to assist with communication.
Their free hotel accommodation for longer than 8 hours layovers is certainly a winner just as I welcomed being met at the gate and escorted through the airport to the lounge when I had connections there. Last year, I was even offered a hotel for a 6 hours layover because "the lounge here is not very nice". Small but pleasant perks as is the use of lounges for even silver members when they travel in economy or free seat selection in rows with bigger pitch that other flyers have to pay extra for. They called them SkyPearl economy seats and indeed there was more space and only a few of these seats were taken. It was nice to put the armrests up and stretch out across the empty seats.
CZ responds to customer complaints - I should know after making quite a few of them for matters like food, use of J toilets by economy class passengers, etc.