AC has full-flat beds on all of their big birds except for on 3 767's which don't actually have a C cabin. I do most of my flying on AC/UA and I can say that I'm content when I fly AC and dreading every mile even in C on UA. UA C really sucks, the only good thing is upper deck on the 744.

My choice of airline would depend on where I was flying into in China. ICN is better connected with China than NRT, so OZ might be the most convenient and it would certainly beat taking a domestic CA flight out of PEK. If you're going to PEK/PVG, I'd agree with a previous poster that CO EWR-PEK is probably the best option. NH is better than CO and probably better than OZ, but unless you want more miles or a stop in Japan, I don't think there's any point to go through NRT.