As a frequent flyer with MU (more than a dozen flights per annum) , here's a brief insight into what they are like - in short, they do their job but don't have very high expectations, especially when compared to Etihad.
For their A330-200s which serve this route, don't have high expectations on the hardware. They have two business class products on offer - on 332/33E they have the 2-2-2 configured Business Seats - lots of legroom which makes it very comfortable to sleep in but lacks privacy. On 33H (newer A330-200s) they have the Zodiac Cirrus Seats in a 1-2-1 configuration which is much better in all aspects, apart from the legroom which can be a bit short.
Economy Class is the same on all of these aircrafts in a 2-4-2 configuration.
The entertainment system is horrible on these aircraft - I would download something to watch on my own device - there are little movie choices on their system which is also very old.
The cabin crew is usually quite nice but some might not be very fluent in English. They are generally very nice and happy to help.
From the aspect of food - again don't have very high expectations, especially if you are not a Chinese diet. Their Chinese food offering is OK, and if flying from PVG its reasonable, but I have never tried the Western options and they are probably not very good. They offer Chinese tea which is a nice thing, in all cabins. Since I am under 18 have never tried alcoholic options, but there doesn't seem to be a lot either.
Other things to note - They do not offer online check-in for international flights, so you will have to select their seat through their website. Remember to use the Chinese website as the foreign websites don't seem to perform well. Their app is another alternative and does offer English services.
On the ground, they offer lounges with freshly cooked noodles with soup which is always a treat and one of my favourite aspects of the experience.
Do let me know if you have any questions - more than happy to help.
P.S. China Eastern offers a substantially better product on their later A330-300s (33L) and on their newer aircrafts (A350/B787-9) which has fully enclosed suites. But I'm not aware whether they will change the aircraft to Abu Dhabi anytime soon. Dubai is served by these newer aircrafts.