Id Choose the all Power Vampire Killer the Sorcery Whip. I do feel that some parts of its story that do bother me, but to me I just think of the story I gave it, that always does the trick.
It's a great weapon The best ever made, there is non more powerful, and it can adapt too, it can be swung on or used as a shield, by spinning it, or can shoot fire balls, and it can be transformed from leather to chain growing in power and hight, and by attaching things to it can be transformed even more. so id say the Vampire Killer is beyond any weapon in AD and any real hunter can make it work for him by becoming one with it, And using it Unmatched power.
The Hunter whip is like its weaker Brother, a great weapon but no Vampire Killer. Combat cross is great but lacks any real power so... yeah.
the Vampire Killer is the winner here.
also there is the undead killer and Langs holy whip, But they never get a mention.
I can't remember were I saw it but was the vampire killer going to be a sword at first, but they couldn't make it look good so they went for a whip instead.