So what is a zero fret?
A zero fret is a fret in the position that a nut normally would be and the concept is that an open note will have the same character as a fretted note since both notes are created from the same string to fret intereaction. I’m not really sure that I buy that, or that it makes that big of a difference, but it sure makes nut making and setup a lot easier.
When you use a zero fret configuration, the zero fret sets your action height at the end of the fretboard, the nut simply controls spacing. This makes intonation better at the lower frets and allows me to get a consistent reasonably low action.
The downside, if there really is one, is that the bridge height needs to be at a sufficient height to have an angle greater than that of the fretboard. This means that the higher up the neck you go the higher the action will be and the more compensation will be required at the bridge. Conceptually with a traditional nut you should be able to have lower action across the entire fret board, but it’s still very difficult to achieve.
I may change my mind tomorrow, but for today i can get excellent results using a zero fret and I’m going to stick with it for a bit.