Guess I expected more.  These socks feel very nice and fit well but I think the -30 below rating is a bit over the top.  The 'Extreme Cold Winter Socks' description made me think I wouldn't have to use the foot/toe warmers...wrong.  All in all, you still need a good pair of boots and if you have been using the warmers, you'll still need them.
My experience, your mileage may vary.