The iron takes longer than a heat gun, however, with a heat gun you need to be VERY CAREFUL around seams and any overlays. If you are not careful the seams will pull and separate and the overlays will shrink and pull.

I suggest using a heat gun on a "non-favorite" plane first to get the "hang of it". That way when you mess up (not if, but when ) you won't be ruining the covering on a favorite plane.