We have a bunch, and they simply don't last. I never dry them in the d oryer, but the plastic gets these tears in them, or the fabric shrinks up. The quality varries between the fabrics. My red checkered ones shrink up weird and get all bunchy. My blue ones disinegrate.
If you're willing to replace them often, they're great. But I was hoping mine would last longer than they have.
Oh, and they work really well. They just don't last long.