Personally, I haven't noticed any difference in durability regarding the spring's longevity. I got keep on covers for my original Zeros when I switched to SP, so I have yet to wear out a plate. The walkable are a little lower profile, so they are more comfortable to walk in. Obviously better traction than uncovered originals, and IMO, better traction than keep on covers as well. I have had both keep on and walkable covers come off, but the walkable seem to hold up better and I've seen several shops in my area that sell replacement covers, whereas the keep on's I have to order online.

Hope it helps.