I have flown to China over a dozen times and most of them were on Air China... I have found that it was often delayed (especially coming out of China) and they used to have a great safety record however I think it was a bit tarnished in recent times... would have to double check.

It is indeed almost always the cheapest option by a lot however.

I personally have no problem flying them at this time but I may have missed some news about their safety record...