41magfan what wiggys do you use? Have you used it down to it’s rated temp or past it? I ask because as my post above says people either hate them or love them. I definitely like the 2 bag system.
I bought my first Ultra-Lite (20 deg) bag about 20 yrs ago. I've used it in the 20's wearing nothing but a short sleeve t-shirt, skivvies and my hiking socks. I'm confident I could use a 30-35 Deg Wiggy bag down into the 20's wearing a base layer or light clothing …. which most people do. I have another UL bag with the Overbag system …. I intend to just try the Overbag as a stand alone some day.
Wiggy bags are hard use items having durable zippers and robust fabrics. They aren't built to be light or compressible for its own sake.
I used to prefer high-end down bags/quilts (WM or Katabatic Gear) for short backpacking trips. They're light, they compress well and the moisture build up (from body perspiration) isn't an issue in most cases. But like I said, if my life depended on a sleeping bag, it wouldn't be a down product by ANY maker and it sure wouldn't be a non-Climashield synthetic.
Regardless of the marketing spin, there are only two general types of synthetic insulation; continuous filament and chopped staple. Neither are new and neither have demonstrably changed in many decades … they just keep changing the name. Climashield is the only CF insulation that I know of that's readily available to the consumer.
I find that a disproportionate number of people that don't like Wiggy products have never used them and many just don't like the proprietor …. and I get that, but it is what it is.
As a point of context, I'm a convert to quilts and my current kit consist of a 20 degree Climashield product.