tried them in the same guitar, directly after one another:
AHB-3 has more output and thicker mids (full spectrum, no dips like the SH-6). Less bass end low mids which makes it tighter.
The AHB-3 has an very aggressive upper mid spike, but the SH-6 has this also but maybe not as extreme. SH-6 has more lowend and a more and more searing top end, but they are both ceramic screamers.
AHB-3 has some EMG 81 qualities.
SH-6 feels drier, if that makes any sense.