Those clip-ons aren't nearly as effective in keeping the slop off you and your drivetrain as full fenders. It also takes like 5 minutes to take off a pair of fenders, if I wanted to, which I don't. The permanent mount fenders also definitely look better than those things pictured in the OP.
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"Let us hope our weapons are never needed --but do not forget what the common people knew when they demanded the Bill of Rights: An armed citizenry is the first defense, the best defense, and the final defense against tyranny. If guns are outlawed, only the government will have guns. Only the police, the secret police, the military, the hired servants of our rulers. Only the government -- and a few outlaws. I intend to be among the outlaws" - Edward Abbey