I have several bikes fitted with plastic and VO alloy fenders. VO fenders are a little harder to install than plastic, partly because you have to tweak the attachment points with leather and rubber washers and dampeners to kill the noise you get with metal fenders. Metal fenders rattle and amplify road noise; plastic fenders are silent.

Once installed, the VO fenders look very good, better than plastic, in part due to the nicer looking stays and attachments (which detract from appearance on plastic).

My VO alloy fenders (VO sells various models in stainless steel too) are still like new after a few thousand miles of road use, with no dents. I suppose this might not be the case if I had traveled dirt/gravel roads instead.