Great report. I have the same itinerary departing mid-February. I usually do Miles and Copay with UA. This ends up being the same price but without the Miles (~$2400).
I guess I don't like the "connecting flight" operating procedure at PEK. I wonder if if in the future if Hainan plans to be able to 1) print the PEK-BKK boarding pass at ORD and 2) go through 'standard' connecting-flight security in PEK like NRT instead of being ushered out to the ticket counters.
Cheers.