They are useless except for rocks getting caught up in there on dirt roads. I don't drive dirt roads. I leave that up to the Duke boy's from Hazard county.
Exactly. They won't keep water off the rotors (they only protect one side!), and really, water doesn't "stick" to the rotors anyway. They might keep a little brake dust off your suspension components, but that just means its more likely to be on your rims. :D
Most modern cars don't come with them from the factory anymore.
But, if anyone's looking for a set or two, I have a couple from BBP set ups, PM me for pictures/details. I run 11.75" rotors anyway, so the 10.87" dust shields don't help me.
But beyond looking stock, I don't see them serving any useful purpose.