TPE transit is much better (no need to go through passport control, immigration, customs to enter, then the same again to exit, then security, as you have to do in PVG or anywhere in China), and CI is also a safer choice than any China-based airline, esp. as you are not flying over China's mostly military controlled airspace, which may result in serious issues in case of weather issues yet China ATC not allowing civilian aircraft stray from the few narrow paths that are open to rest (all the rest is military exclusive use). Also, it helps that CI crew don't smoke in flight, while MU crew/pilots often do. Plus, in case of any IRROPs, if flying through China you may be left stranded, while in TPE transit is so much easier, CI will surely take better care of you, and the CI lounge with its cooked-to-order dishes is far superior to anything at PVG.