Wonderboard is cement board, he might be thinking of the Hardiboard
stuff.

Opinions on it.... Hummm...

When I built my shower I used Wonderboard. I've seen showers that are
at least 20 years old and they are holding up just fine with Cement
(wonderboard)

The hardiboard stuff is promising though. It cuts VERY easy. You can
actually
nicely score and snap it. Wonderboard is a bit more difficult to work
with in that
respect.

I would say give it a shot, it can't hurt to try it. Any decent
backing for a shower is better than using drywall (greenboard or
regular).