It's well designed and has a lot of nice features. Works well with my sleeping pad, even though it's not a thermarest (Klymit static V). The whole system is pretty well thought out. First problem is rating, it's not a 0 degree bag, it's probably closer to 10F. Second is the bag comes with a storage sack (good) and a "field sack" (useless) which doesn't have compression straps. I just use a compression sack for a 25F synthetic bag I have (7"x18") and it works perfectly. You could probably go down to a 6" diameter compression sack.
This review was written in the old system and had content requirements that are different than reviews written today.