Originally Posted by hindukid

Sounds like your real question is:

"Is UA C enough of an improvement over SQ Y to justify the extra mileage required for the award, the cost of going from BKK to SIN, and the extra connections needed"

If that is the question then my answer is no, I would take SQ Y.

If I was forced to choose between UA C and SQ Y with all other things being equal then I would certainly choose UA C.

However I have never flown any of these so my advice isn't worth much.