I bought this for the first time as I was down to my last drops of 18. I was eager to compare the two heavy-weights side by side. Rare is a little more daring, slightly spicy yet smooth and old. A savory mix of plum, raisin, sherry and spice. The dark fruits and old leather dance beautifully together in your mouth. The finish is sticky and keeps going and going. I found myself licking my gums long after my glass was empty. 18 is more refined, a bit more smoky, less spicy and for me doesn’t seem quite as aged. Both are wonderful, and I can see cases on both sides for which is the better bottle. In the end I give the edge to Rare Cask, it seems more daring and has its own special character that I love.