I really like the knife and it's ability to wound even zombies. But then I tried out a shock platoon which sometimes stuns enemies in a comical way. Shocking! 
After getting used to the game again I find that stunning and then following up my attack with a knife is really effective.
On the other hand. Pipe shotguns are crap. They are really slow, noisy and sometimes you can't hit the broadside of a barn with them.
One night I fired my pipe shotgun at a dire wolf at point blank range twice. It didn't even phase it. So I switched up with my knife, which at least hurt it.
After getting used to the game again I find that stunning and then following up my attack with a knife is really effective.
On the other hand. Pipe shotguns are crap. They are really slow, noisy and sometimes you can't hit the broadside of a barn with them.
One night I fired my pipe shotgun at a dire wolf at point blank range twice. It didn't even phase it. So I switched up with my knife, which at least hurt it.