For non-elite, it makes no difference which *A you choose (as you are saving RDM).

For elites, it depends on the airlines policies on courtesy to elites, and how many EQM you can score a *G.

No offense, but some *A airlines does not give a fxck to *G at all, but the only guaranteed *A benefits. For example, SQ, NH, AC.

For example, if you simply want *G, Aegean Airlines may be the best (4000 EQM for *S, then additional 16000 EQM for *G).

But in your case, if you expect some perks (and SQ is willing to do it), then KrisFlyer will be still your own choice.