Back in the 80s, some of the older NCOs used to talk about sewing a woobie onto a standard army wool blanket. The woobie was softer than the itchy wool and the blanket helped keep wind from passing through the woobie and sucking away the trapped heat. Sound reasoning but obviously did not pack down too small and I stuck with the sleeping bag with a woobie liner.
In the pre-gore tex days, you could take two woobies to the tailor shop along with a rubberized nylon wet weather jacket and they would sew a woobie material liner into the coat. Not breathable, but better than the cotton field jacket IMO. Great for Germany.
The Kifaru woobie is really nice and warmer than the issue one. It really packs down well too. This can be a detractor if it is really hot at night. I still use an issue woobie when camping in the summer. Otherwise the Kifaru holds up well and drapes nicely with no cold spots.
Wiggy used to make a heavier woobie which did not pack down all that well and was much thicker than the other two. Don't know if he still makes them
If you have the coin, the Kifaru is good kit.