Instruct: Classify a given review into positive or negative sentiment.
Query: Speed Safe Fail, Very Expensive for Quality

I purchased a Kershaw 1970BLK - Blur Black "Ken Onion Design" with speed safe assist opening. I've worked knife several times, and it fails to open all the way every time, has never actually locked into place. I've got $9 cheapies that open without failure, every push on the thumb knob. Returning for refund, maybe I just got a defect, family member swears by Kershaw.