hmm
Well I am using one now. But I wouldn't recomend them unless you are experienced with heat sources frankly. The *can* short out etc.
I use mine 10-12 hours a day often less as it is hot here right now, and I also have it on wood. in a special bag it came in, under a rubbermaid with has layers and layers of paper. I always make sure it has a cool off period at night for 12 hours or more. And so far so good. No burning, constant temp, etc.
But if you are not experienced in setting up heat sources porperly and maintaining them (timer for cooling off, close eye on it at ALL times, signs of shorting out/burning/hot spots constant in tank temp monitering etc) to avoid fire then I would suggest just buying a reptile one which is proved to be safe with long term use.
bmm