We have used these and Lock Laces for our boys, ages 8 and 10.  I wanted to like the Xpand better, I like their look and the fact that you cannot really tell at first look that they are not real laces with the ties hidden.  First, the Lock Laces...they lasted thru the life of the shoe and did not show wear and tear, mostly because the plastic is on the top middle which sees less action.  Also, the strings on the Lock Laces never tore or thinned. Now, the Xpand laces...they have plastic tips on the ends of the lace which you could wear on the inside or outside.  My sons have sensory issues, so we placed them on the outside.  With that placement, the plastic tips got quite worn quickly and did not look nice anymore.  Also, the string wore out near the tips showing wear and looking stretched.  One time the plastic tip caught on a backpack as my son was climbing into his seat in our van and the lace tore!  It took a lot of work to open up the nib once again because it was so worn out and slightly disfigured.  However, once we got it open we were able to trim down the lace and reinsert it.
Another aspect of the Xpand laces are the tiny parts.  If you child loses a tiny part before you even get to use it because he was checking out the system, you can order replacements.  That is right, you will pay about as much for the replacements as you did for the laces.  No sympathy from the manufacturer on your plight with kids.  With the Lock Laces there was no issue with tiny parts.  We have also tried the little plastic bands that go between each row where the shoe laces belong...no bueno.  The next set we are going to try are the one handed laces.