I have not look at china eastern FP recently but last time i looked at it is was really not interesting and I would assume hard to manage (things change quickly in China so this might be outdated). on the other side if you are doing lots of domestics flights in china it might be worth to credit them to a local FFP because still lots of fare don't redeem miles with FB and perks of being FB Plat on domestics flight are most of the time nonexistent.