I didn't need a boot that would be warm down to -100, but decided to go ahead and get a heavy duty snow boot since the less warm/less waterproof ones were also over $100. I'm sure this boot is extremely warm and waterproof, and it is certainly very soft and cushy inside due to the pillowy inner liner, but I would not recommend this boot unless you truly need to stand for long periods of time in extreme cold and wet conditions. This boot is very stiff, fairly heavy, and quite difficult to walk in (similar to ski boots). My biggest complaint is actually due to the fit.

I have normal width size 7 feet and typically fit true to size in most running shoes and boots. My calves are very athletic and my heels are not narrow, so I've never experienced boots that moved around too much. The length of these boots is just right and true to fit. However, even with the straps cinched as tight as possible and wearing 3 pairs of ski socks, the width of the heel is so wide and the space above the top of the foot close to the ankle is so great that my heels were swimming. This is very comfortable, but when I walked my heels would move up and down at least 2 inches (and this is before the boots were broken in). While there is nothing to rub your heel on, so impending blisters were not an issue, having your heel move up and down is extremely uncomfortable and annoying. I had trouble walking without tripping on my flat hardwood floor, so I can imagine that walking in the snow in these would be a nightmare and a little dangerous. I am returning these boots for a different pair.

[Note: I returned these boots and tried the similar Baffin Women's Ice Field boots. I had the same problem in the Ice Fields with the heel width and space above the top of the foot close to the ankle. I believe this is due to the stiff, straight rubber behind the heel that protects and warms the ankle; it does not flex in even when the straps or laces are tightened.] Overall, Baffin makes a very high quality and clearly well-manufactured boot for a great price, but the fit on both the Women's Impact Insulated boot and the Women's Ice Field boots allows the heels to move around way too much.