US Amex membership reward points will transfer to Krisflyer on a 1:1 basis. If you're going to be based in SG, Krisflyer may still be a good option, particularly for flights within Asia. The availability can be much be better than through some other *A programs. I've also found upgrades to be very obtainable within Asia -100% on about 10 segments this year involving TPE, HKG, SIN and PER.