Pretty well everything I got is from Orvis. Thanks for the tip, I'll have to check them out. My boots have the felt bottoms and that's all I've ever used. I've never tried the rubber soles but from what I've heard, they tend to be slippery in water so that's why I've been shying away from them. I know there are various different types of rubber that have different properties just like in car tires (Michelin). I thinking the softer rubber would have better grip and perhaps this is what they're using here. But with softer rubber, it'll lose in durability but then Orvis have a great return policy and warrantty on their stuff..There is a new Orvis boot (Orvis boot Pro) with a Michelin rubber sole....amazing ...like walking with Velcro on your feet. Rocks in my rivers are covered with slime...these are great boots! They are way lighter than my Simms and provide better support. Also way cheaper...take a look!