One thing to notice about the better reflective material is that it reflects well regardless of the angle of incidence. The stuff on the left reflects great, as long as the light is hitting it fairly square on. If it's wrinkled or around the side of the vest, it reflects very little.
The better stuff forms a solid white line regardless of wrinkling or angle.

I thought the old one was pretty good until I got this. Then I threw away the old one.