Originally Posted by
starsocean
Thanks Gary, It's really helpful. It's now very hard for me to decide whther to use KF mileage to redeem SQ's biz or first class ticket (but need to pay very high tax and YQ), or to redeem other SA carriers seat (anothers mentioned it's not worth to do it as only KF and lufthansa's mileage can redeem SQ's biz and first class ticket).

If you have miles in other programs, or if you don't mind buying one-way, I would definitely do Suites if at all possible.
If you bought LAX-CTU with cash, you will be able to redeem CTU-NRT-LAX in ANA Business (no First Class) and SQ Suites, for 100k miles one-way plus ~$240 in taxes. And that'll an experience you won't forget anytime soon