International reputation of SIA and thai airways are very good. I only fly these two if i go to Bangkok.
If i fly to UK, i fly SIA or BA, if i fly to holland, SIA or KLM, if i fly to germany SIA and lufthansa.
What air asia ? what myanmar airlines ? rubbish.
I've got a different opinion about SIA. Comparing notes with others SIAs standards have really dropped. Different passengers look at different things but some of the complaints are similar
One of SIAs most irritating practise is that they like to hit you with overweight luggage penalty even if it's just 1 kg overweight. This was when oil prices were cheap & when flying in "business" class. This is poor behaviour from a so called world class airline:(
I've flown with other airlines as an economy passenger & had obviously overweight luggage but was never penalised
It's when you fly economy that you really see how poorly SIA treats it's passengers compared to other airlines.
I've seen many cases of the pinkerton behaviour among the staff of SIA:(
Don't forget that in the case of an accident, as a Sporean you or your family will find it hard to get compensation.
The last flight I took with SIA was on a flight to NY. Stewardess was rushing & almost hit me with the meal cart

SIA flights are uncomfortable because they are always packed. The most comfortable flight I ever had was flying economy with Qantas to Europe. The flight was 3 quarters empty & every passenger had a row of seats to themselves which made comfortable beds.
For short flights to Bangkok I usually use Air Asia, it's cheap & reliable.
If anyone is flying across the pacific, instead of flying SIA economy, they should look at Eva Air's Evergreen deluxe class which is cheaper than SIAs economy class & much more comfortable as the seats are similar to SIA's business class.
If your company is paying for the flight you can of course choose SIA. However I don't think SIA provides value and when I'm paying I look for value.