I like them both! They both have their good points. With the graphite, I can put any string on it and it does not move (much) to warrant an adjustment. To me, you have to like the graphite sound to appreciate it. It is somewhat brittle sounding for the lack of a better word. Tons of sustain though!
The wood necks are definately warmer sounding. They can also be adjusted to have just the right amount of bow. With my wood neck Alembics they can be played not plugged in and can be heard well. When I mess around with the graphite bass unplugged, it is hard to hear tone just string noise. Make sense? The wood I guess resonates much better.