In my opinion I would go with the muzzleloader. A muzzle loader is probably more accurate, huge selection of different bullets to use depending on your needs, you can use loose powder to work up a load that is very recoil friendly and deadly on deer. I myself have killed a lot of deer with a 240gr XTP bullet and 80 grains of powder. The recoil is about nonexistent and many of the deer have dropped on the spot. You can even drop down to a 200 gr bullet and still have plenty of power for a deer. That being said I have very little experience with slug guns.