I'm using my On-sale-at-Kohls iron and it has been fine. I'm not sure it has auto shut off? But I turn mine off immediately anyway. You know how you automatically retract your rotary cutter when you are done cutting? That is what I do with my iron. With 4 kids at home there are constant interruptions and I'm afraid I'll walk away, forget about it and burn the house down!
I took a class with Judy Irish last weekend and she uses a cheap model too