Each of the two have benefits and drawbacks. Acrylic is shinier and polycarb is stronger. Acrylic is less expensive but easier to crack. Polycarb is more impact resisant but easier to scratch. They are both stronger and lighter than untempered glass; acrylic is 4x to 8x stronger than glass, while polycarb is about 200x stronger.
A video produced by the motorcycle windshield company National Cycle illustrates some of these differences by showing the effect of various projectiles and weapons on both acrylic and polycarb windshields.
By the time you finish watching a faceless guy in the video hit the windshields with everything from a slingshot to a baseball bat (and a hammer, shotgun and semi-automatic pistol) you'll get the idea that polycarb bends (and scratches) but doesn't break; and that acrylic stays stiff and shiny but cracks and shatters under impact.
Another way to show the differences is to list some of the common uses for each of these two materials.
Common Uses for Acrylic Sheet:
- Fish tanks and aquariums
- Animal and reptile enclosures
- Retail product displays
- Storm window linings (interior layer)
- Hockey rink glass
Popular Uses for Polycarbonate (Lexan):
- Race car windows
- Transparent visors for hockey and football players
- Window well covers
- Re-usable drinking bottles
- Computers: Apple, Inc.’s MacBook, iMac, and Mac mini
- Machine guarding glass
- Laminated layers of polycarbonate can be engineered to stop various size bullets