I'd still rather have a smile, fake or not (don't we all use fake smiles every day of our lives?) , than some miserable person completely ignore me or look like I've just made them do something that is totally demeaning and inappropriate for cabin crew.
I also think the food is good as well. There's always Asian and western choices. Then there's the entertainment system which, once again compared to BA/Qantas, was superior. Last BA flight I took from Jo'burg to London (economy, sadly) had 12 channels, not on demand...
I suppose, at the end of the day it depends on the cabin crew and plane. I find the SIA are at least consistent in their approach and there's something about those kebayas that's very alluring!