I notice a fashion for "D" necks .. to the extent that a bass dealer I talked to says he's been asked to modify the odd bass to D before someone will buy it. My own bass is Eflat and when I bought it ( some time back!) the matter wasn't something that mattered or got mentioned.  Likewise 'cellos have E and F necks and anywhere in between, but it's never mentioned. I like the Eflat neck on mine as it puts my thumb in the same place relative to fingers as I use in other positions and a b