I dont think anyone can comment on how good or bad Voronin is until he actually plays for us.
It is IMO ridiculous to have any sort of opinion on a player who hasn't even kicked a ball for us yet just because none of the 'Big Clubs' were interested in him does not mean that he is going to be an average player or the other side, that he is going to be a world beater,watch him play a few games and then decide but at least give the guy a chance FFS !