I have flown on all (or almost all - since every time you turn around there is a new Chinese airline in the domestic routes).... China Eastern is on a lower end of the quality assessment. Shenzhen Airlines - not bad, Air China is by far the most reliable, China Southern - not bad on international flights...OK domestically. The list can continue for a while...
Even non pure domestic airlines can experience the dreaded huge delays in the congested Chinese airspace - case in point - Cathay Pacific or Air Macao (my most recent flight from Beijing to Macao was delayed by 4 hours!)

Back to China Eastern - I have flown both domestically and international with them - e.g. Shanghai to Tokyo. Here is my report from the first flight I took internationally with them when I lived in China...

http://www.china-finds.com/travel/20...tern-airlines/

If price is your objective though - you have to consider them....

Just completed four-segment trip on China Eastern (Dec 3,2016) that includes two transpacific segments. I was concerned when I read the headline of this thread, naturally, but those four flights were like any other flights I have flown. No surprises or problems. Aircrafts were clean and nice, on-time performance, decent food. I would fly China Eastern again anytime.