Where are you guys getting this??!?!!!

Yes, polyester is as much a structural resin as epoxy. For the 1950s, 1960s, and early 1970s it was about all we had and the fiberglass boats and planes from those days (both models and person-carrying) are still holding up just fine... including the little 14' racing sailboat I have out back and the 36/600 R/C boat in my garage.

The strength and stiffness of our fiber reinforced plastic (FRP) composites -- whether they be carbon fiber, kevlar or other aramid, or good old glass fiber -- the strength and stiffness come from the fiber. The role of the resin is to bind the fibers to one another and to the substrate, if there is one.

If you want reliable bottom line advice on this, it looks like you need to go to the sites of the composite suppliers... they post a wealth of reference and how-to information.