So a Kelty Cosmic Down 20* F bag costs $80 and the cheapest I can find a Light Year 20*F is around $160. Any reason for the difference in price besides a few ounces of difference in weight and the zipper at the foot of the bag?

What I'm asking is, any reason to buy the more expensive bag? Right now I'm figuring I'll buy the cheaper one and put the money towards my next bag.

Let me preface by saying that I have not used either bag. The specs look a little suspect. Both bags are EN comfort rated to 32F but the lightyear has 23oz of 600 fill while the Cosmic has 20oz of 550 fill. Sound like the lightyear should be the warmer bag. However, if you are not going to be out much at 32 then it really isn't an issue so get the cheaper bag.

Decided to keep my REI polar pod 25*F synthetic bag and buy a kelty light year 0*F bag for when it gets below freezing.

I figured a synthetic bag would be better for warmer and wetter environments while the down bag would be better for colder places where I was more likely to run into snow than rain.