They work better how? Are you saying the same force applied to the plastic hat will protect you more than the same force applied to an aluminum hat?
Plastic lids have some bounce in the shell, it’s a property of
all of the plastics used to make hard hats, except maybe the phenolic/fiber in the MSA Skullgard. It redirects whatever hits your lid. If something heavy enough hits it, the shell will crack, and still redirect whatever hit it. Now, if something heavy and pointy hits, it’ll crack and spear you. But chances are the weight of whatever cracks that plastic lid
and is heavy enough to not be redirected and spear you is heavy enough to break your neck.
Aluminum just dents. If something heavy enough hits it, it dents into your head. Something heavier and pointy will pierce straight through the lid. A lot of guys knock the dents out. Those spots will
not take another hit, because the material is not as strong.
As somebody who’s taken a 25 ton WLL Crosby shackle to the head from a long ways up, my plastic lid did its job in a way I
very highly doubt a Mac T or Skull Bucket would-it dented a job box. I’m pretty sure it would have dented all the way to my skull and I would not be able to type this out.
If price was an issue, saying as most plastic lids are less expensive than an Aluminum one, people would not buy the MSA Skullgard, which I think is up in the $125-175 range depending on what you buy and where from.
So, in a succinct manner, yes, they do work better at protecting your head. They don’t look as cool, and they don’t have as long a service life. But, I’m more interested in going home than looking cool.