I see tons of n-gons in Andrew Hodgson's work there, @CreativeSheep .The only person who said anything about modeling totally in n-gons is yourself. Read the thread again, look at the referenced images -- the argument for n-gons seems clear to me, but your's is not. What is the point you are trying to make exactly?
@CreativeSheep mate, I think you may be confusing yourself. Why would the sub-d mesh be going in-engine? As I mentioned above, the sole purpose of the high poly is to bake down from. It's probably best not to advise people on things you are uncertain of yourself.