I noticed, I had a 16.92k ohms pickup with an Alnico 5 and it was slightly lower in precieved volume, while the ceramic version of that pickup was hotter meaner and seemed louder .:wrf:
With the Alnico 5 humbucker, I just pumped in my SD SFX-1 Pickup Booster for a hotter punch from that pickup.
Ceramic is much stronger than A5. It's got more of everything, and a fairly different overall character as well.
It has more highs, more mids, more bass, and bigger output - hotter, meaner and louder is exactly what you get soundwise.
Ceramic's highs are aggressive, so it generally does better in heavier winds than light ones - can be a bit fizzy, especially in a low wind.
And ceramic's bass is huge & very tight, one reason why it appears in nearly every humbucker intended for metal players.
Long ago, when Seymour was doing mostly rewinds, he also sometimes used to customize humbuckers without rewinding by replacing the regular A5s with ceramics. These pickups were said to have been "Seymourized."
A8 is not quite as hot as ceramic but it's a bit bouncier, while its highs are hot yet not quite so supercharged.
That makes it sort of a middle ground - often good for beefing up an A5 pickup, or taming the fizz of a ceramic one.
Either way, it changes feel as well as the output.