Ive never had any delays entering into China - so far I have arrived into KMG, CTU, PVG and PEK. CTU and PEK have very smooth transfer procedures. PVG isnt as good for domestic transits as so many flights fly to SHA.

Transit at HKG is excellent, as bags are directed to your final city in China, although the Dragonair transit staff are usually cranky first thing in the morning.

At PEK China Southern and Eastern fly into the older terminal, which is a pleasure to use as it is not busy. The walks at the New terminal at PVG are tremendously long.