since you have flown Asiana presumably you have some miles in Star Alliance somewhere. So it is probably sensible to keep accumulating miles with whichever program you are using.
I believe TG's A345 gets good marks for Y comfort. 36" pitch, individual IFE. It is a long time in the air though. When the JFK-BKK route was going I flew there in premium economy which was OK. You get some more legroom and recline so it might be worth the extra couple hundred $$$ to some one who is tall.