I have killed and seen deer killed with both. A centerfire rifle is the more effective weapon in my opinion. Higher velocities and better designed bullets give you better BC's and transfer more energy causing better wound channels.

I live in a shotgun only area so I use a slug gun or an inline muzzle loader. The newer saboted shotgun slugs are pretty much just an inline ML with smokless powder and a cartridge. They pretty much use the same pistol XTP type bullets driven at higher velocities. They work and they work well out to 100 yards and maybe beyond, but not as well a centerfire rifle with the right bullet.

If I had the choice I would use a centerfire no questions. I would use a .243 over the slug gun if it were legal where I lived.

Just my opinions anyway.

Paul