I flew CA J on an A330 a couple months back SYD - PEK and PEK - HND (different seats, the A330 seats are identical to the TK J seats). IMO, it was like flying UA but with a really good crew. Food was slightly better, drink selection was about the same, but the crew was better and more attentive than your standard UA international crew.

Duvet is nice, you get a L'Occitane amenity kit, and you get a pair of red slippers. On the SYD - PEK (which was an 11.5 hour redeye) I slept for roughly 8 - 8.5 hours.

The lounge at PEK isn't great though AFAIK if you're flying UA you'd be using the same lounge so it's a wash in that respect.