So the basic idea is that you can use them like pins, one on each side. Some people have issues with the "third leg" of the snappi getting unhooked or putting too much pressure on boy bits. IMO, great concept, I was excited to try them.
The old version did not look like the promotional images. It was HUGE, like an inch wide almost, well mainly the stars (the hook/anchor ends) were ridiculously big. But most importantly, they just weren't that stretchy. There was no stretch-release elasticity factor, they were basically rigid. I could get them to work but it was difficult and I didn't love them.
The new ones are MUCH MUCH better, it feels like the snappi rubber, much more elastic (stretches and bounces back like a snappi). The heads/stars/hook ends are more reasonable.
Here's a comparison pic: from top to bottom, a regular diaper pin, new boingo, old boingo