I got these soft leader fins blades on warranty when my medium leader fins broke. Everyone says you should use medium but I had to see for myself. I actually really like the soft blades in the summer when I am just wearing a rash guard and almost no weight. I had no problem diving 70-80 feet with the soft fins and they are super comfortable on the feet.
The problem appeared when winter came and I started wearing wetsuits with more and more weight. It’s hard to come of the bottom with the soft fins, and it gets harder the more weight you have on. So these became back up fins and I eventually sold them.