It all depends on what you're after... There's no way in hell I'd buy a "fragile" high modulus graphite bait stick for fishing yellows - gotta go fiberglass for that kind of stuff. In the same way, I would hate to fish a soft fiberglass stick in the bay with 6# test when I'm trying to feel the difference between a blade of grass and a spottie breathing on my plastic.

Higher quality graphite is generally considered to be graphite with a higher Young's modulus and lower tensile strength. In other words, it's stiffer (therefore you need less of it to make a certain stiffness or a rod) but has less tensile strength. The chart below might explain it a little better.

http://www.leonadivide.com/adam/stress-strain.gif

TL,
Adam