I've flown Asiana several times (always in F class long-haul on 747-400's & a few times on short-haul narrowbodies. The service is excellent, and at times quirky.

Until recently, when commencing the approach for arrival after a long-haul flight, Asiana would run a "stretching" video, featuring comely fa's performing a bunch of stretching routines to Korean music. While the video was being shown, the FA's would be in the front of each cabin w/ their backs to the screen, doing the same movements.

I couldn't figure out how people in coach could do these excersises w/o body-checking their seatmates...

With respect to safety, my understanding is that the much-publicized poor Korean safety record is due to Korean Air not Asiana.

Most long-haul trans-Pacific Asiana routes are code-shares w/AA, so you can pick up extra miles, etc. if you use this service.

Have never flown China Airlines, so can't provide any useful info on them.