if you look at a bag with 800-900 fp down and a same-rated bag with 500-600 fp down... the first one will pack smaller as well as be lighter.

But, some people don't care as much about a few inches and a few ounces as others do. smirk

I've also noticed the higher quality down doesn't leak out the seams as much. Fewer actual feathers in the mix, apparently.
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