Are the claims of a stiffer cage on a front derailleur being the silver bullet to eliminating chain rub and improving shifting performance nothing more than a clever marketing ploy, or is there actual science backing up the benefits of increased cage stiffness, and if so, whats the optimal level of stiffness for riders who dont want to sacrifice a smooth ride for the sake of sharper shifts, and can we trust the manufacturers specs when it comes to measuring cage stiffness, or is this just another case of the numbers game, where the real-world performance doesnt quite live up to the on-paper promises?