Worth it for a few hundred to fuck around with? I see they pop up pretty cheap now and then, and Warmoth also makes parts for them too (300 and 500, I think).
[VIDEO]http://www.youtube.com/watch?v=dgki-wJM_jI]-Modelling Guitar Series - Part 3 - James Tyler Variax (JTV69) vs. Variax 300 Acoustic Comparison - YouTube[/VIDEO]
The older one sounds more piezo-y, but still not bad. Both sound like shit on 12-string and dobro, neither of which I'd use that much anyway.
I always thought the Variax acoustic sounded far better than the electric one, but thats because I wanted it for the Sitar sound and Shamisen sound.
They are cool though, worth having to piss around with, just don't expect exact LP or Strat tone I guess.