I think you're starting to see the recommendations diverge in a fairly common way.
For the best warmth/weight ratio, nothing beats high quality down (esp. the 800+ fill stuff used in the higher end bags). There's a reason the ultra-light backpackers choose down (and often just a quilt, rather than a full bag): down is the only way to get down to freezing temps with a bag at or near one pound.
The Wiggy's bags take a different tack, using synthetic materials and a modular, military-inspired designed (outer bags, etc.). They're heavier and bulkier than down, but tough and flexible. Though any good down bag is plenty water resistant and not likely to have loft problems unless it gets truly drenched, poly is undeniably better if your bag gets soaked. That makes poly a good choice in very wet conditions (less of a concern for sub-freezing temps, more so in cold rainy muck). It's also good when you can't predict where you'll be, and what kind of other shelter you'll have -- which makes it good for military and survival situations, where you may have to improvise on the fly and maybe sleep out in the rain.
For me, down now wins most of the time if I have to carry it. Doubly so because I spend much more time in desert/mountain conditions, which means dry and chilly at night, and warm days that make extra bulk and weight on my back miserable.
Poly, to me, is something that is only desirable when car camping, or perhaps in wet, damp conditions (canoeing, coastal kayak camping, etc.). I do understand why hunters often go more in that direction -- damp fall hunting weather, transportation to help with the weight (whether a four-wheeler, horse/mule, etc.), and possibly a bit of a cultural inclination toward military-surplus style gear, too.
