Varieties of scotch- there are a few different regions, and they tend to have different flavor profiles, though each maker does vary. Speyside is the stuff like Glenfiddich, which are sweeter with honey and grass and boring stuff like that. Highland scotches vary widely, but they'll often have smoke and peat flavors, and be somewhat sweet. Islay scotches like Laphroaig are famous for being astringent, full of peat, iodine and smoke flavors. I've heard Laphroaig described as "like licking the inside of a chimney". I can't get enough of that- to me, it's wonderful. To others, it's disgusting.
Scotch is a complicated world that I'm only beginning to learn myself. If you don't know anything about it, I would go for the bourbon for this. And I would make it a point to learn- the process is incredibly tasty.