The ceramic magnet gives more high-end cut and a tighter bottom end chunk but cuts mids and then palm-mutes don't sound as full. Alnico is better for doom metal and leads, and this can also be enough of an advantage in some other styles that the slight tightness advantage of the C8 over the A5 is not worth the loss in other areas or the extra brightness, which can be a bit much and kills lead tone
Nailbomb comparison:
https://www.youtube.com/watch?v=X2kvQkpz5sMThe effect of the magnet swap is quite consistent, and can be seen with the Black Hawk as well. I bought the A5 Blackhawk twice and I've always been happy with the A5 Nailbomb, but I am a doom metal player who wanders into death metal or black metal territory now and then.
Black Hawk comparison:
https://www.youtube.com/watch?v=2qacdnnbe2kThe acoustic qualities of the guitar will also affect how the pickup sounds. I had the A-Bomb in an Epiphone Explorer (Limba /Maple w rosewood / TOM, 24.75") and the A-Hawks in Schecter superstrats (mahogany body / bolt maple w rosewood / floyd rose & mahogany / mahogany set w ebony / string-through TOM, 25.5"). The only variable that didn't change was string set, D'Addario EXL117 (string tension slightly higher on the Schecters). The A-Hawk bridge is my preference, just because it's less hairy and sits in the mix better with a two guitar band when I'm doing rhythms, and has a very nice lead sound
