The problem with beading is that small beads will cling to the surface and in salt water will leave spots as the water evaporates, called spotting . Unfortunately, there are no lens coatings that are truly effective against spotting in salt water. As for our lenses, they are the highest quality polycarbonate which means the surface is very smooth. We use a special hardcoating process that also makes the lens very slippery. The combination of those two things makes the water sheet very quickly.
Shields do work great for surfing.
We have not received one complaint about spotting. Remember, if you are not truly happy with your Shields, return them for a refund.