Something about not 'changing the intonation' on the guitar was on the promotion for this.
It raises the action, as you would expect but... way more than you would require.... you will not be fingering the fretboard when this is on(for this reason, the intonation is different, due to the extra string tension required to fret the notes).
Other than that, its a great piece of engineering but if it were a slimmer piece of metal, it would be more useful.