I use straps for my 15" and 18" deadlifts. A kid who was training with me got up to about 495 and one of his straps, NOT APT STRAPS, broke. I went up to around 700lbs and my APT basic straps were going strong. We loaded the bar up to 765, and we decided that the bar would be ruined before the APT straps would. =]
Lesson: APT straps are strong!