Caring for Cast Iron
i have found that my very old cast iron pan (one my mother got at an estate sale years and years ago) is superior to my 'pre-seasoned' pan. it has a smoother cooking surface and is far less likely to stick.
that being said, even the pre-seasoned ones, if they are properly taken care of (or seasoned from scratch as mamiller35 suggested) can become as good as nice, old, well-used pans.
also, regarding bacteria - i don't use soap on my pans ever. but i do preheat my pans very well before each use (to kill any leftover bacteria) and i heat them with oil after each use (to kill bacteria and to refresh the seasoning). Detergent works as a physical agent to remove most bacteria (yes, that's right, not all). Heat kills bacteria. (food-service training). of course, i still say do what you're comfortable with - if you won't use the pan otherwise, use soap! :-)

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