actually, how are they in general? always been infatuated with them, but could never talk myself into it. like i said though-mainly interested in the acoustic sounds.
I had a first generation Variax and I did play it a couple times at church. I had mounted a Roland GK MIDI pickup on mine so I could add in synth sounds as well (like backing up the 12 string acoustic sound with orchestra strings...etc).
The acoustic models sound better than solid body electrics with piezo bridges (like Godin or Parker). They still don't sound as good as a nice acoustic, but they are close enough that most people would need to hear them side by side to notice a difference.
check out this link, at about 5 minutes into the concert you can hear an acoustic and a Variax playing almost the same guitar lines, but there's a clear difference in tone.
I can't speak for the Tyler Variaxes, never tried one. They are supposed to play better, but I'd not be surprised if they had exactly the same models as the previous gen.