I like mine. Well made. I've had it for five + years? Same comment as Ed as to zipper length. The zipper length works great for getting in and out of the bag, it's just not a full length zipper which I'd rather have. So I can open it up like a blanket on warm nights. Ed mentioned the more recent models may have a longer zipper?
Sizing: I have a regular length. Some may find it a bit snug, it is an ultra light, I'm 5' 7" and 175 lbs. Its perfect for me girth wise, may be not so for bigger guys. Throw one on the floor at REI, etc. and try it on.
It packs down nice and small and is lightweight.
Temperature Rating- I sleep cold anymore, if I've been hiking/hunting all day (tired body), so I add 5 to 8 dgrees to any bag, the same with this one. However, it was right on the money for 15 degrees when I tested it in the backyard (i.e, with a nice and rested body and a nice warm supper inside the house).
-Hope this helps. I'd listen to Ed, his vocation is testing equipment, literally.
I also bought the Hydrogen (30*) for summer nights, but found I like the Helium better in mountains (summer).
