I've only tried 3 Islay whiskies to date: Lagavulin 16, Ardbeg Corryvreckan, and Bunnahabhain 12.
The Corryvreckan was a real pleasure. In the nose I got a medicinal note along with some smoke and tar, and hints of dark fruits. On the palate, smoked pepper steak comes to mind. I got a trace of vanilla, some dark fruits that I couldn't quite sort out, a bit of saltiness maybe. In the long finish, the smokiness faded just enough to give the sweetness a little more traction. Really good stuff!
The surprise was just how approachable it was neat. The high ABV was pretty warm on the first sip, but after that it settled down and I thoroughly enjoyed it.