I won't comment on CX as I haven't flown them recently, but I did a YYZ-TPE-PVG a couple months ago that I was quite pleased with. The seat was spotless, great cabin service, good (clean!) mattress pad and duvet and lavs remained clean throughout the flight. TPE is a convenient airport to connect through and EVA has good lounges. The YYZ TPE flight gets in around 6am, so if time is not a concern take an evening flight to HKG and spend the day touring around Taipei.
Obviously, a nonstop flight gets you there faster, but if that isn't a requirement I would recommend EVA over AC.