I used it on the wood stove chimney on the sticks 'n' bricks. Later had to make some other repairs that called for removing some of the Eternabond. Did not try a heat gun, just a knife and pliers. It came off, albeit with some effort.
It was still flexible, and where it had been adhered to the aluminum, wood, nails, screws, and stuff, it was still stuck down strongly. It's good stuff, I wouldn't hesitate to use it. I would, however, advise you to be sure to clean off the surface like they tell you to do. If you try to put it down over dirt, loose rust, wax, or plain old dust, it will stick mightily to all those loose things and come right off the roof. Mighty expensive method of cleaning the surface, if you ask me. But a great sealant on a clean and dry surface.