Timing is everything - I just performed a little experiment yesterday. I tried out a new DeArmond Turbo-Jet bass pickup which came with two small ceramic bar magnets. It sounded pretty good - played about 1/2 hour. Then I swapped the magnets for two HB alnico bar magnets. The amp settings weren't changed - nothing was changed except for the magnets. I was surprised because I think it sounded better with the ceramic magnets - definately a little punchier and maybe a little more clear or focused sounding. On a guitar I have no use for ceramic magnets, but on a bass I might even prefer them, on that pickup anyway. I should say that the alnicos didn't seem as strong, which doesn't make sense because they're supposedly stronger than ceramics of an equal weight (I didn't weigh them, but the alnicos are about twice as wide - and I didn't didn't make any strength test, they just felt like they didn't have as much grip). I might make some longer poles and double up on the alnicos, four in all. I intend to make the same experiment on a MightyMite P-90 which I've altered for bass.
Edit: Been doing a little research and need to make a correction. As far as the weight/strength thing goes, I just read that in the sizes used in pickups the ceramics are stronger than alnicos - also, more magnetic strength will give a brighter sound. I guess that explains why I alnicos I used seemed weaker...they likely are.