I use it.
I don't see how there could be ANY long-term effects with this stuff. I have (2) 4' lengths of 12" wide heat tape from reptile basics that wrap my 15 gallon drum fermentors. There is so much surface area/watt, that it never really even gets "hot". I think at 4' in length, I am running somewhere around 80-90 watts of heat. Don't think of it like a 100 watt light bulb. There is SO much more surface area than that of a bulb. At any given time, I can hold my hand on it for as long as I want. There is absolutely NO risk of this thing heating up too hot and damaging something. Plus, I am running it in my chamber where I am lagering one beer and fermenting an ale with this setup. (see my signature)