They fit correctly, secure well, and make the job of cutting crown molding a virtual breeze.  No more messing with making 2 adjustments (bevel and miter) on your saw.  Set these up once for the width of the crown molding that you're cutting, and you'll typically only have to make your miter adjustments, which is easy when your DeWalt has the positive stops for the crown molding cuts.  In addition, due to the way they hold the crown molding, they eliminate the mistake of having the molding facing the wrong way when you're making your cuts.