I don't use a lock at present, and the one I have uses a flat key, but the article is interesting.
It seems bizarre to me that the Kryptonite manufacturer says it never really tested to see how hard it is to pick the locks.
Faster than a speeding bullet, word is spreading across the Internet, through cyclist hangouts and into bike shops that all it takes to open a circular-key lock, like the one on the famous U-shaped Kryptonite-brand lock, is a ballpoint pen.
The U-shaped Kryptonite - consisting of a steel curve with a locking horizontal bar - is a must-have among serious bicyclists. It can cost more than $50, and for an extra $10 to $20, it comes with a guarantee that says the company will pay customers more than $1,000 if product failure results in the theft of a bicycle.