Did a Macallan tasting a while back. Fine Oak 10, 15, 17, then the sherried 12, 18 and Cask Strength.
Of the Fine Oaks, the consensus was that the 15 was the best. It was more complex. A few people said it was their favorite of the evening. (By the way, I am told that the Fine Oak 17-year is actually 18 years old. They call it a 17-year to avoid confusion with the sherried 18-year.)
I'm not a huge fan of the sherried Macallans. I usually detect lighter fluid. That was okay at first, but as I found it more and more often, I decided I was not too interested. So I tasted the 12, and it was... not as much lighter fluid as the last time, but I still disliked it. What was it this time, cough syrup? Then I had the 18. I was very pleasantly surprised. I found it to be excellent. Nice complexity and no objectionable notes. By far, my favorite of the night. Then we moved to the Cask Strength. I normally find this one very good, in spite of the lighter fluid. Again, I didn't really detect the lighter fluid, but there was something else that kept this one from the top spot. The Cask Strength is, dollar-for-dollar, Macallan's best product. If money was no object, I'd be buying the 18-year. While I enjoyed the Fine Oak 15 year, I wouldn't go out of my way for it.