The Newflex 8mm is what I recommend to most people because it has an ideal combination flexibility, cushioning, traction and durability while being very lightweight.
The Newflex 5 mm is exactly the same but a little bit more flexible and less durable. I offered for those who prefer a thinner sole to to Be closer to the ground.
The 6mm Smooth is mainly for people who don’t want the tread pattern of the 8 mm.
The traditional leather sole is a great option for those who don’t want rubber, prefers something more traditional and natural, and I don’t mind doing more maintenance themselves. It is also much better suited to the forest and not concrete. It will not last as long as rubber, it will soak up water, and will delaminate much more easily.
The Minimalist Vibram 1 mm is only for those who want the absolute minimum because they are committed to minimalist footwear.