Just in case people didn't see this link in the other thread, I thought I'd start a new topic since this is brought up a lot here.
The biggest point Sean makes is that playing the Variax acoustics and having them sound good requires a light touch - a very light touch, really. I think this is where many of the complaints come from. You can't necessarily treat the Variax like an acoustic guitar and strum the crap out of it like you would a real acoustic guitar and expect it to sound good.
Anyway, here's the link again.