as willi said each rig works in its own right, obvoiusly chod rigs are designed to be fished over choddy/silty bottom, But i will almost always cast a choddy at a showing/boshing carp and aslong as i feel the lead hit the bottom i know its presented ok, choddys are not for weed, spend abit of time casting a lead around and then decided on rigs, hard bottoms - bottom baits,,,, silty - choddys/stiff hinge etc. ....etc etc etc IMO anyway
good luck fella