Turbulence affects all airlines equally, it shows no favouritism. That said, CI's safety record does leave a LOT to be desired, especially when you consider that one of their A300-600R crews got things disastrously wrong on approach to Nagoya and stalled, dropping a few hundred feet onto the airport and the plane exploded with about 180 dead, putting the crash into the All Time Top Ten. Then about a year or two later, exactly the same thing happened at Taipei, again with the loss of all aboard after the crew let the automation get away from them. Plus they put a brand new (as in, three weeks old or something) 747-400 into the harbour at Hong Kong. However, they're not in the same league as Korean Air - Flight International published their bi-annual safety audit and it was like, Korean Air, Korean Air, Korean Air. And on the cover of the issue was a Korean Air MD80 broken into pieces after overrunning the field at high speed and sliding into a ditch.
As for China Air Lines' on board service, it's OK, the food is quite good, printed menu and newish, clean planes with moving maps etc on the video screens, so it's quite pleasant if not outstanding. I have heard through travel agent friends that their business class and first class are below standard, food on a tray, no individual TVs, basically just international economy class with an amenities bag and a big seat.
I've flown with them a couple of times and would recommend them overall, but they're not Cathay Pacific.
fly Saha Air 707s daily from Tehran's downtown Mehrabad to Mashhad, Kish Island and Ahwaz