I've played them on several occassions but they're not for me. My reservations are -
It's really on electric guitar, it doesn't feel right if you're used to playing an acoustic. The body's too small and the neck too thin.
You need in-ear monitoring to play it well, there is not enough volumne from the bare strings to work with well
Some of the sounds are very good BUT I think most people would only use 3 or 4 at most.
The retune option only works with monitoring becauase what little you can hear is at odds with what you're trying to play.
I've seen a couple of electric guitarists use them effectively where they want an acoustic sound in a heavily miked enviroment and it does cut out the feedback problems.
Like the Line6 Bass Guitar (good but not gorgeous or radical enough for the price tag)it's an idea looking for a market. Could see a lot of studio use by sessions men and as above, lead guitarists needing the acoustic sound, but that's about it.