Originally Posted by
YuropFlyer
Yes, Alliance might play a role too.
However, as I stated already, int-int connections in PEK are usually NOT delay-prone, and TPE can be hit hard by typhoons. Someone saying that TPE is less of a risk to fly through int-int in, say, May-October (Typhoon season) than PEK, would get laughed at by myself.
For me, flying Taiwan - PEK a lot, most of delays are from Beijing. Taiwan has Typhoons, but chance I would say 2-3% (3-5 days out of 150 day season). Beijing has bad smog (air) days at least 30 days a year currently, and air traffic control delays as mentioned before make the on time rate much lower than Taipei, if your worried about on time flights.
I do like Air China for mainland flights, as I fly star alliance, thus in Taiwan I use EVA air more, CI less. Air China has nice new 777-300's 747-800's with nice seats, but to me (based in Taiwan I am bit favor Taiwan culture, so maybe not fair view but my personal feeling) I think your fellow passengers maybe be better on CI than CA (ie less distractions).