the amsteel from rockstomper seems to be the cheapest. they make no claims of it holding up to heat. depending on your winch, it uses the drum as a brake, and on power out situations you are fighting the brake and producing heat, well, normally the wire acts as a heatsink for the drum.
depending on your winch. my 8274 doesnt use a drum brake, so i dont have to worry. scott said that it should be fine unless you power out for more than 20' wich seems pretty useless. freespool doesnt use the drum, so there is no worry there.