The best neck..

Sustain is nice but who holds down a note for 5 minutes in any song? So, above all, you need TONE and ATTACK. This means bolted, not neck through. No dead spots or warped neck. This means carbon trussrod. Maple neck and rosewood fretboard. 5 string sounds better when you get a longer 35" scale. Angled back +-12 degrees supports a better tone/sustain aswell. But it makes the glued peghead a weakpoint mechanically. My design solves this. And makes tuning a lot easier as I will explain later.
If you want a neck like this VOX HUMANA, holland is the place to be! They have developed their own fabrication of the carbon rods and they are fine, skillfull guitarbuilders. Furthermore, they can build one offs like my design. To get a good soundtransfer between neck and body I opt for a multiple screw (6-8) extra large connecting surface.