My family is going to be traveling from Orlando to SE Asia (Vietnam) next summer - hopefully using Delta Miles. We're hoping to get 1 Business Class and 2 Coach seats (Mom, Dad & 2 1/2 year old - don't really want to subject Business class to the baby for 24 hours).

Looking at the "virtual tours" on Singapore's and Korean's website makes SQ look like Air Force 1 and KE look like a Greyhound Bus - Is there really that significant of a difference? I've flown SQ coach once before, but have never flown KE. If we can't get the free tix on SQ, should we spend the same number of miles on KE, or just spend the $$$ on SQ?