Although I have never preferred to use a S/G over a centerfire rifle I have been forced through the years to use one in S/G only areas. My first deer hunting was done using S/G rather than rifle and my last use was while hunting on Ft. Campbell. I've killed a good number of deer with a S/G shooting slugs and two while shooting buckshot. In one case I was shooting buckshot over a .308 in a combination rifle/shotgun and in the other case I was shooting buckshot and slugs mixed in the same magazine of my A-5.
My experience tells me that from now on, if/when using a S/G for deer my choice will always be using a slug. At ranges over 10-15 yds the slug has vastly superior penetrating qualities. At those ranges muzzle to 15 yds, I'd think most anyone hunting deer should be able to hit a deer-sized target with a slug.
Others may have differing opinions and I know that some areas such as N.C., S.C., and other southern states have a huge tradition of using buckshot, especially hunting deer run by dogs (legally). One of my buckshot deer was shot during such a hunt. Actually hit first with a slug at about 5-8 yds, I managed to pull the trigger a 2nd time before he hit the turf, but only skinned the hide of his butt with the buckshot load, next in line (thank goodness!)
I think it has alot to do with where you are hunting. If you are hunting in areas where the shot distance is very short, like the north woods of Maine, then buckshot is a good way to go. My father and grandfather both shot bucks with buckshot up there. However, if you are going to be shooting at substantially further distances, then I think you need to have a slug, so that you can reach out and touch them. A shotgun with a slug and a good scope can be a great hunting weapon.
Area has a lot to do with it for sure. I have both types of shells at home. Have i used either to shoot with, no not yet. I would love to get a dedicated slug gun with a scope. I have read good things about them.
Others have offered up a sighting of roughly 2 inches high at 100 yards as a good sighting scheme. In my own experience I have come to favor a sighting of 3.5 inches high at 100 yards. This allows for the individual to hold dead-on (directly in the middle of the top and bottom) the animal out to roughly 350 yards.
Magnum calibers such as the 7mm Remington and 300 Winchester will extend this slightly. At 400 yards I hold directly on the backbone of the animal. The drop at this range allows the...