They are the warmest boot out there.... If you don't mind sweaty feet. They are a bit heavier, and a lot bulkier, but a lot more waterproof!! The traction is about the same, maybe even a bit better.
I don't like them, but they are the boot of choice for real deep cold temperature, a lot of the mushers up here are using them. The Yukon Quest dog sledding race, that is starting today here in Whitehorse Yukon, and go all the way to Fairbanks Alaska, 1600km, most mushers and handlers will wear them!!