Best way to pack a sleeping bag?

When I was looking at sleeping bags at REI this summer, the very helpful REI employee suggested stuffing my sleeping bags inside out - saying that it's much easier to get them stuffed quickly and compactly. 

I tried it, and am not finding a huge difference. 

Do all of you stuff inside out or rightside out? Have you noticed a difference? More on certain kinds of bags or in certain situations?