Cool, but not that impressive
These are the icon that most people think about when they think about winter boots. I got a pair a little over ten years ago and they are still in pretty good condition, although I don't wear them that often. I think there are plenty of better boots for the price. I worked for an outdoor retailer at the time, so I think I paid about $30, which was too good to pass up. I would say the -40F rating is way off. I have a pair of Rocky hunting boots with 800g Thinsuate that I would say are as warm as the Caribous and way more comfortable to walk in. If you like the style, which is super cool, go for it and buy them. Otherwise, Backcountry has plenty of other styles that will perform better.