I have always found that SQ happily provides every published *A benefit for ones status level... and as a *G I have certainly been invited to board "early" with SQ in the ports from which I have flown with them...

..the problem we have here on FT is that people will not (apparently) read what these published benefits actually ARE.. (and *S gets very little on any airline as already mentioned)

... hence all these threads grumbling about upgrades (!!) and "preferred seating".. neither of which are, or have ever been, published *A status benefits.

SQ does allow one to pay $50 for an exit row seat at time of booking... which I consider pretty decent value on say SYD-SIN.