Sustain

Has anyone here ever used the sustainiac or Chandler Tone-X Guitar Preamp before, because I am interested in them and im not sure if it would be worth buying and where do you mount the Tone-X switch? it says it requires no routing. and is it sustain or just controlled feedback.
Your thoughts and comments would be very appreciative.
http://www.sustainiac.com
http://www.musiciansfriend.com/srs7/sid=030828194409064033138041356784/g=home/search/detail/base_id/100524