Cush comes from the midsole. EVA is plush, but turns to mush under heavy loads. For serious schlepping, you need polyurethane. A rubber rand fends off scuffs and extends the life of the upper. Vibram is the reliable benchmark, but other rubber compounds are plenty durable.
Rugged conditions call for deep lugs.
In truth, boot care's a lot simpler than history would have it. Here's how to keep your walkers alive. Your leather footwear will stay soft if you apply a conditioner such as Biwell or Nikwax Leather Conditioner. Use warm water and a soft nylon brush. Buy a shoe tree.