I'm not sure what a satisfactory answer to this question would like like. I probably wouldn't pay $400 for 600fp sleeping bag... though there are circumstances where it might be a good deal I guess.... a -20°F bag? I am always looking for a good deal. The last two bags I have bought have been quilts from enlightened equipment. They seem like a great deal to me. Before I bought the EE quilt I was strongly considering a western mountaineering bag and a feathered friends bag. Both are more expensive but seem like a good deal for something you can buy in a shop (with the requisite overhead and middlemen costs).