Re: eNut!
Personally, I'd go for the Earvana nut instead. The one advantage of this system is that it works with Floyd Rose guitars. The Earvana nut involves no permanent modifications to the guitar, whereas this would need to be attached to the first fret somehow. The Earvana nut is also designed to correct the tuning at the first five frets, as well as improve it throughout the rest of the fretboard.
Ryan