You will probably feel similar recoil with both. Recoil is related to the velocity of the projectile, the weight of the projectile, and the weight of the firearm.
Slugs are almost specifically used for hunting. Buckshot is great for self defense. The most common self defense load is 00-Buckshot.
With Buckshot, you're not trying to hit multiple targets (although it's possible), you're just trying to make sure that you hit 1 target. With 10-15 balls going down range, the odds of one of these .33-.36cal pellets hitting a kill zone is pretty high, and there is a really good chance that you will land 5+ in the kill zone.
But yeah, you got it right
Also, a good slug can be used out to 100+ yards, where as buckshot is really only effective out to ~50 yards.