I flew MU business about three years ago when they restarted the SFO flights. I found their service very good and the seats were lie-flat and larger than CX business. I usually flew OneWorld and have never flown MU afterwards. They had lie-flat for both my HKG-PVG and PVG-SFO flights.

I echoed three areas of concern:
* Cell phones are not allowed to be turned on even on airplane mode. However, there is no problem with tablets.
* Chinese security is tight on number of phones and power banks - 2 and 2. The capacities of the power banks must also be clearly labeled. I don't know if that applies for transit.
* ATC delays in China. Long haul flights are usually on time, but short haul and regional flights may not. That means your layover is unpredictable, and there may be a connection risk on your return flights.