Does anyone have any experience on how much smaller a MW3 packs down than a MW4? I have a MW4 and I love it, but I've begun to think that it takes up too much room in my pack during spring, summer, and fall.

I'm thinking of getting a MW3 to make some room and save some weight, but I don't know if a MW3 would really free up that much space. Would I be better off getting a Greylock 3? Unfortunately I don't know if I'm sold on the idea of a torso length under quilt and a pad.

Thanks for the help.