i have an epiphone zack wylde les paul, which i like the feel of, but im not happy with the sound of the (passive) emg hz's any more.
last year i bought a proper gibson zack wylde les paul (it was too cheap not to, and i made a nice profit on it) . it was an awesome guitar, but the neck felt that bit too chunky for me... anyway when run through my marshall it didnt sound that much better than my epiphone. the active emg's were more defined, especially in the mid range, but they didnt give that fullness of tone i wanted. i play with not too much distortion so that i can really put my 'feel' into my playing. i tried it with the gain wound right up and thats where there was the most difference, again in the clarity of the mid range tones, which are dreadful with the emg hz's.
however if you played the two guitars unamplified you could hear a massive difference in the quality of tone and the whole resonance of the instruments. the gibson just sang and the whole guitar felt alive, the active emgs really didnt do the guitar justice.
anyway, the point is that i reakon my epiphone would have sounded almost identical to the real thing with the same pick ups and the gain turned up. so if you want zacks sound, an epi les paul with the zakk wylde emg active p/ups and a marshall amp is a good place to start.