I have the black ones, but don't use them anymore. I don't know if I buy the 'break them with leverage from the frame'. These things are burly. I think you're bike tube would crimp before they'd break. However, the tubular lock thing kills it for me, as does master locks response to the issue ("there's no problem...").

Also, the keys are a super soft brass (or were when I got mine). I wore through both keys in one year of medium use. ML will replace them for free, but it's a PITA.

In the end, I found them only marginally more convenient than a chainlock. I'm way way way happier with my onguard pitbull mini-u.