If u actually plan to take EVA, China airlines is about the same as EVA, doesnt make much difference. I have taken both before and it doesnt make much difference in the services and the seats.
If u really want comfort then Air Canada is better but its a bit more expensive, i think. I am paying more than USD 1600 to fly from SH to Calgary on the 26 July and returning on the 8 Aug. But the air tickets for other airlines is also about the same price now, so i would rather take AC instead.
How much u paying for SG to Calgary?