First off, if you're one of the people who've gotten this to work consistently, congrats and I'm glad you're happy.  There seems to be a lot of good reviews, so good for them.  And it is a great premise, the books/DVD are very well done.  Where it falls short for me is in the actual device.  The plastic 'fingers' tend to drift a bit (they are removable), and they hit each other and mess things up.  But the major flaw is how it attaches to the guitar.  It clamps to the neck on the sides, however, the Chord Buddy needs to stay above the strings (so as to not hit the wrong notes), so it also needs something to hold the top solidly.  But any pressure on the buttons causes it to 'fall' down a bit, making contact with the wrong strings.  I'm going to try to clamp it so this doesn't happen, but with the finger drift, I'm not sure this will work anyway.  One wonders what would have happened if they had used better materials?