I have a good lock but there is only one way to keep a bike secure. Keep your hand or your butt on it. Even with a good lock- I am loath to leve my bike unattended- even in the designated bike parking lots.

But in one town that I go to there are security cameras around the Bike parking lots. Not certain if they all work- but IF someone does take a bike- they run the risk that they would be caught on camera and identified. It has stopped bike thefts in the designated areas in that town.

Occasionally I have to leave a bike to go into a shop. I take out the front wheel quick release and take it with me. As soon as you lift the bike- the wheel will fall out.