Had it. I've gone DIY SuperSpeed sticks -> Rypstick -> The Stack. The Rypstick is a good product, and I had a great experience with it and their supporting ecosystem. I actually did the consultation with their personal trainer Sarah and ended up buying a few months of fitness programming from her. The Rypstick takes the negatives of the SuperSpeed system (multiple sticks) and solves that with the changeable weight design. All that being said, the app sold me on the Stack (despite