I got a Zoo Med Betta Leaf Hammock and my Betta loves it. In less then a month's time, however, I noticed the wire rusting. I wonder if I was overzealous in positioning/bending the original leaf. Anyhoo... I complained Zoo Med about it. They said that should not happen and sent me a new one (no cost to me).
Not sure I'd recommend buying one. But if you have a problem with an existing one, don't hesitate to contact Zoo Med via their website. They were amazingly responsive.
If my new one goes south, I'll probably follow those wonderful DIY instructions to make him a new hammock. Honestly, he uses it a lot!