I've only used one set but I am ordering checks from another company and will shred the WM checks. No matter how carefully I try to tear the check out, it looks like I gnawed it out. And I consider it a success it I get it out without tearing. The duplicate check can hardly be read when I finally get the check out.
I don't know if WM does their own checks or another company does them for them, but I'd like to know so I can avoid them too!