Thanks to all, and in particular, sbm12. I fly SIN-KUL almost weekly. I generally fly MH as I can check in at KL Sentral and avoid the zoo that is KLIA MH economy counter.

I had hoped that if I flew SQ, I'd achieve a few benefits.

a) Accrue mileage and more importantly, segments... but it looks like I can only do this if I exclusively book SQ flights which, on average, are S$70 to S$100 more expensive than MH or MI.

b) Take advantage of the business class line at KLIA... although I think SQ would be loath to turn me away with an SQ reservation code and a *G card.

c) Use the lounges - of minor importance since I do these flights so often, I try to make my time at the airport as short as possible... Sunday evening flights out of SIN to KUL are usually very easy.