I had a West Marine Brand and some other (?) marine mat over the years and they either failed to grip the deck or provided only limited cushioning. I hear the Seashock brand has answered all these issues and is worth considering?
I have had custom Sea-Dek pads made for my last two boats. They don't have as much cushion as some of the pads you buy at West Marine but they have a good non skid to keep you from sliding around. The pads have a sticky back that will adhere to the deck and will not come off. They clean up easy. Little pricy but worth it in my opinion.