I had a CA-UA connection there in December. My CA flight from ICN was delayed, and by the time I got to a transfer desk (CA couldn't issue my BP in ICN), the agent called UA at the gate, who then refused to issue the BP (it was after the flight was under gate control). The CA agent at the counter gave me a UA phone number, some paper for immigration saying I had been rebooked on the next day's flight to SFO (I was traveling to ORD) and told me to call them to get rebooked. When I pointed out I didn't have any money, so I couldn't use the phone, she gave me a phone card. This was on Christmas, so merry Christmas from UA.
I found the UA baggage office and went there (as I had checked bags) - the staff there were actually helpful and tried the counter, but nobody was there. They then told me to go to a CA counter and see if they could help. I went there and they, after initially insisting my CA flight wasn't late (I never even brought it up and tried to get them to help me), called someone from UA over and they had rebooked me on an AC flight that night.
Definitely not going to transit in PEK again.