i run fenders on all my bikes. it looks like (to me, anyway) that your fender struts are pretty cheesy. plus, they've got a lot of extra parts to rattle around. i usually use WALD fenders, that are heavy duty, and have been around for a hundred years. they still make them, along with struts and other brackets.
here's a link to a place: Fender Parts | BikepartsUSA
i've heard of people using undercoating spray paint on the insides of them, too. i think i'm gonna try that out on my next one.
just make sure they don't come loose, or you're OTB.