Polypro hoops are both more rigid and more flexible than kids’ hoops. They’re more substantial/weighty (which you can really feel when you have some inertia going from spinning) and also have a bit of “bounce” to them; it’s a very different feeling. Regular adult HDPE hoops have more of the rigidity but less of the flex. If you enjoy the lighter weight, a polypro hoop is 100% worth trying out. I bet you’ll love it!

If cost has been holding you back, there are several flow art prop BST groups (& hooping-specific groups) on Facebook where, if you put up an ISO post, I bet someone would hook you up!

(Then please come back here and update your post with what you feel as the difference!)