If earning miles are not important to you, I will pick EVA Air.
EVA Air's inflight product, catering, and amenities are league ahead of Cathay.
Some YVR flights get Aria now, but I still prefer EVA Air's seats.

Most importantly, you get full flat suites all the way from YVR to SIN on EVA, as EVA Air uss Boeing 777-300ERs on its twice daily flights between Taipei and Singapore. Cathay has a long history of last minute aircraft substitution, especially SIN is no longer an Airbus A350s only.

EVA AIr's lounges are pretty subpar on all three stations - Taipei, Singapore, and Vancouver, but I value inflight service better and not to mention lie flat suites all the way from YVR to Singapore.

Carfield