I've read a few posts lately that suggest that CC is better than OC because you retain the element of surprise.

Coming from a martial arts background many techniques were more effective if you added and element of surprise but these were static exercises and the idea that the BG would wait until you surprised him before continuing to kick your butt ludicrous.

I believe this is the same for handguns. What's going to happen? A BG assaults or targets you but then...AHA! You show them your hidden weapon and they are too shocked to continue?

I believe that rather than an element of surprise you have to cultivate an aura of preparedness and awareness. Take the sheep, wolf, and sheepdog comparison if you will. The wolf knows not only the sheep but knows the sheepdog too and avoids the one that doesn't appear to be an easy mark.

He looks like a sheepdog, acts like a sheepdog, he must be a sheepdog.

Whether you OC or CC I believe you need to project the image of one that shouldn't be messed with and that is what is most valuable to you. The wolf wants easy prey so that they have more chance of success and less chance of failure or injury.