I just looked at a Rush with the assist mechanism today. The safety is meant to keep the blade from opening in your pocket, so you put the safety on when the blade is closed by simply moving a lever on the back of the knife behind the assist lever. Opening the knife using the thumb stud was difficult since you're actually working against the assist mechanism. Also, I found closing the knife took more of an effort than with a normal one hand operation via a thumb stud. I'll probably get a Sirus with the ATS 34 steel, since I think it's a good EDC for the price, but the assist mechanism is nothing more than a novelty in my opinion.