The average guys is going to be better served with a bag versus a quilt, and a 20 degree bag probably has the most utility. The thing I prefer about a bag is that you can use them as a quilt in warmer weather or cinch the hood all the way down and get less heat loss in colder weather - I guess I would say you can be comfortable through a wider range of temps with a bag. On a couple of occasions I have had to cinch the hood down so there was only a tennis ball-sized hole to breath through. A quilt just won't hold that like a hood with draw string - especially if you move around when you sleep like I do.