OK - a bit more from Rick Turner's article:
"You're compromising equal temperament; the guitar will now favor certain keys over others. This is fine as long as you know what you are doing and have another guitar available when you want to play in Bb!...A system that changes the harmonics of open strings and the tuning of open strings also creates a bias towards certain keys" (I suppose these would be the guitar-friendly keys, maybe G, D and E) "and against others." (guitar-unfriendly keys like Eb?)

I had the Feiten system installed on my Lowden two years ago and have been very happy. However, the fiddler and accordionist I play with keep telling me that the guitar goes sharp when I capo up, and tuner checks bear this out. The B and low E strings sharpen more than the others.

I'll call Rick Turner's shop and see if he'd like to participate in this discussion. Meanwhile, has anyone out ther bought a new Washburn or Tom Anderson guitar? I'd like to hear from other users.
Michael