i switched this season from the lake boots to the defrosters, and have found that the defrosters arent quite as warm as the lakes, but they are both MUCH LIGHTER and considerably more water resistant, which is a trade off i can live with.
yesterday when it got to -18F on my way to work, i had the defrosters plus two pairs of defeet wool socks and a pair of the eastman handwarmers that you can buy for 15 bucks a box at sams club, and i did ok. i was still pretty cold when i got there, but i had all my toes, which is no small feat after an hour of almost 20 below zero.
most days in the teens and twenties, i just do wool socks, sealskinz, eastman warmers and defrosters and i'm very comfortable. if you ziplock the warmers as soon as you take them off, you can get a lot of life out of a single pair which makes them a very economical option.
i've been reading a lot about the toasty feet lately so i think i'm gonna hit wallyworld on the way home and grab a pair.