If you're used to 4-string Fenders, it's not that different than a P-Bass neck, as the nut width is wider than a Jazz, typically, 1.75" to 1.5". If you've always played a Jazz (or Ric) it may feel a bit wider. Of course, Alembic will make any nut width you want, as well as the other neck dimensions.
I see it more obviously on the fives (or more). Mine are a 2" nut by a 2.5" 24th fret, so there's not a lot of flare at the high end. It's different on an Alembic, as the 24-fret fingerboards typically place the octave and higher frets further clear of the body than a Fender or MusicMan shape with a 20 or 21 fret neck. I've seen some Yamahas and others where the string spacing is a lot wider at the top of the neck than at the nut. Alembic can do that too.
I preferred the classic taper as the strings are virtually parallel all the way up the neck, kind of like a classical guitar. Just suited me better. Again, though, it's just not a radically different feel from a traditional Fender layout for most guys.
Joey