What's the difference between an infinity (smart) hoop and a traditional weighted hoop?

A traditional weighted hoop rotates around your waist and relies on momentum to stay up; a smart/infinity hoop wraps around your waist on a strap and a counterweighted ball travels along a track, so it can't fall. Reviewers consistently note infinity hoops are easier for beginners and cause less bruising, while traditional weighted hoops give a more demanding workout once you can keep them up.