I have never flown Asiana, although the fact that you can accrue mileage on AA would probably be the deciding factor for me!

I have flown CGK-TPE-SFO and return on China Airlines several times. Coach on China Airlines is horrible. I bring my own food and bottled water. Believe me, I am not a snobby guy and am generally more than willing to travel in steerage to save a few bucks or miles. However, I don't think I will fly China Air again whatever the savings might be.

That said, there was a mistake once and I was moved out of coach to Dynasty Class on China Airlines to make up for it. Dynasty class was fabulous. The food was great, the FA's were super attentive, and the seats were average for first class.

Take it for what it's worth (which probably isn't too much )
-Eastwest