The halberd sucks ass, man.
The Great Scythe is amazing. The R2 does a ton of damage, has great range, decent speed, and probably the best sweep in the game.
I can vouch for this. I wanted to work toward the lifehunt scythe in one of my playthroughs, so I rushed through the catacombs around SL13 to get the great scythe. As long as I kept it relatively upgraded, it tore through everything until I turned it into the lifehunt.
It's probably just an illusion, but I prefer the normal attack animation on the great scythe more than the other halberd types. The heavy attack is amazing through.
The lifehunt is just another world of broken though.