...just don't have unrealistic expectations. This isn't going to stop someone with the sole intention of stealing a board from stealing your board. I cheap pair of snips, or even a strong amount of force will break this thing.
It WILL provide a deterrence, and it will prevent some punk kid from stealing your board on a whim (no one has cutters with them on a whim).
Would I buy it again? Probably not. I bought it b/c I was only a few bucks away from free shipping, so the price difference between this and shipping on my order was negligible. It is lightweight, unobtrusive, so you really don't know it's there. I used it a few times. For what it set me back, I'm happy with it.
But I would not recommend getting this as a "lock it and forget it" solution. Always be somewhere where you can at least have eyes on your board.