The Air China seat is identical to the 2-class UA business class seat, with 2x2x2 configuration.
But what they routed you on looks like a 3-class UA business class seat, which is 2x4x2, with 2 middle seats in each row.
You should push to get the nonstop PEK-EWR; you'll be in better shape, why not ask for that?
That plane is a 2-class UA config, with no middle seats.
The Air China experience is documented here
http://www.businessinsider.com/flyin...k-2013-11?op=1
Same seat as PEK-EWR on UA, meal service your choice. On this one I'd vote UA.