The claim is that it offers 20% more cushion over other running shoes mid soles. Geared towards runners that are heavy in weight or just looking for more comfort in their shoe soles, the extra cushioning, however much, does seem to work out quite well.
The plush cushioning inevitably wears out faster than stiffer, heavier, shoes. The cushion starts to fade at between 200-300 miles, compared to 400-500 miles for stiffer shoes.