simply put, I have been paying over 100 for Penguin brand.  I walk to trains for work, and was wearing out the base in a matter of months.  That + the fact that there was zero traction on the other shows meant they could not be worn in the rain, snow, or ice.  Material is not 100% of the penguin quality but close enough, and good traction on the base for slick surfaces.  I see these lasting quite a bit longer in general, and maybe having a pair of nicer ones that will last longer because of the more rugged use of these.