It completely depends on the other stats, if we're talking low level pking, as in combat levels lower then 60, the zerker will crush, but as combat levels increase, so do the max hits of pures (drastically), they can pull off some miraculous spec's to KO banks.
To Sum up:
Low Level Pking - Zerkers
Mid Level pking - 50/50
High level pking - Pures

