In reply to Galilao:
Just got a pair for the first time. The red ones. For the same reason that I've ben suffering cold toes. Do feel warmer, though I did get cold toes again yesterday so they're not 100% (for me anyway).
They are hell to put on, practice it a few times before you go out. The best thing I heard was put the rubber bit in boiling water for 10-20 mins before putting them on so it is easier to manipulate. I have now bitten the bullet and glued them to the boot as the first time I wore them walking over snow covered heather the gaiters on both feet had peeled back off the toes. And out on the hill with cold fingers they weren't ever going back on!!
I wore them with crampons and doesn't affect them in the slightest. Scarpa boots and grivel G12's and g14's, newmatic binding.
I don't imagine they would ever cause a problem with crampons, unless anyone has experienced otherwise....