Review (4/5): Great for straight, fine hair.
My 3 year old loves the look of pigtails and ponytails, but she hates how tight the tiny disposable silicone rubber bands get (it hurt!). Fabric wrapped elastics just slide right out of her slippery hair, even the Goody non-slip kind. We stopped trying pigtails at all until we found these. They're perfect for her, since they don't slide, I don't have to twist and wrap them multiple times to get them tight enough, and her hair is a great texture for just rolling these out at the end of the day.
You can easily accidentally shoot them across the room because of their thickness and taut stretchability. That's the only con... but it makes for a fun game of "find the ponytail holder."
I can see how these would be terrible for curly hair or hair that is coarse in texture. But for slippery, straight hair, they work great.