Hong Kong by itself, very good...single system operated by the Mass Transit Corporation. They do both metro rail (subway and "regional") as well as intercity express trains to cities as far as Shanghai and Beijing.
I'm not sure about the ontime performance of the intercities (they run every 2 days or so, and 50% is owned by China's State Rail company, which sucks so bad they don't even mention departure times anymore), but the metro rail comes so frequently there is no need for a timetable. However, I did once need to ride the first Airport Express train 0550 and it was about 10 seconds early
Anyways, on top of every station there are signs relaying information about how much time remains before the next train arrives - this is always accurate because data is transferred from one station to another. Nearing arrival of one station, the train trips a switch on the rail and a message telling people a train is arriving is broadcast on the platform.
Regarding China state rail....let's just say I took it once and will never do so again. I won't even comment about on-board services, especially CLEANLINESS. Here's a simple run-through the boarding of a train.
A man dressed in what looks like a PLA General's uniform walks into the "waiting" room - a giant room with about a million people in which you stand. There are no seats.He says, "Train no. 64 heading to Guiyang, please proceed to platform", in rough and highly northern accented Chinese (obviously reminescent of Communist times - this was a station in southern Guangdong, near HK). He uses nothing but a loudspeaker and a 4-foot tall ladder.
Two miniscule doors open and the million passengers file out.
People start shouting, drowning the man's pathetic attempts at Cantonese. The train was scheduled to depart at 1512. It departed at 1549. It was on-time.
You get the point