Clearly, the average backpacker can choose their campsite, and has some control over their situation. In the military, this is not always the case. You'll find Wiggys bags to be heavier and bulkier than most; but they are built to endure conditions that most are not.
My Wiggy bags breathe better than any bag I've ever used. I often sleep under the stars without so much as a tarp for overhead protection. I have woken up with the dew so heavy that my bag looked like somebody pissed all over it, and I have been warm and dry. It's the only bag I know of that I would crawl into wearing soaking wet clothes, and know that I will wake up the next morning dry. Wiggy also attaches a small thermometer to the zipper pull of his bags, so that during the night you can check the temp and compare it with how warm you really are. I know of no other manufacturer that does that.
In summation, I don't claim that Wiggys is the best bag out there; just the best bag for the money when very wet conditions are expected.
When I sleep in a bag, I get all the way down inside the bag. My head does not poke out - I am completely inside the bag. The Wiggy bag is long enough to allow me to do this (I'm 6'1). The moisture permeability of his bag/insulation is so great that I can exhale warm air inside the bag, and the vapor will pass completely through the bag, without wetting the insulation or condensing inside the bag. On a cold night, I can hold the bag to my mouth and breathe out, and watch the vapor condense in the air on the other side of the bag.
My question is, would a down bag allow me to get allow the way down inside it, and breathe through the bag? Or would this cause a "wet spot" at that area?
It is this ability to pass vapor that allows me to hunker down completely, and the ability to put moist, damp clothes inside the bag with me knowing that when I wake up I will be dry, and my wet clothes will have dried - that keeps me a Wiggy devotee; even if it means hauling an extra pound.