I had a little tasting of my own yesterday. This is part of a comparison I made on my new blog: maltsofpandemonium.blogspot.be
Colour: harvest gold.
Nose: less impressive than the 15, one again, toffee and chocolate notes, but fruitier this time: apple peels, banana, dried apricots and oranges, heavier sherry influences, but with grassy undertones and a whiff of menthol. Nice and rich nose.
Mouth: much spicier on the palate, overtones of white pepper, cinnamon and nutmeg. Oak wood and vanilla with hints of almonds. Close to the 15yo on the palate but less refined, with more influence from the sherry aromas.
Finish: very long, slightly bitter and dry, with a peppery aftertaste.
Conclusion: Overall an excellent malt, the problem was that I tried it after the 15yo, which still is in my opinion the stronger of the two. But that doesn't mean the 18 isn't an great malt on its own. There are probably others who will find the 18yo more appealing, for the same reasons that I prefer the 15yo. (De gustibus et coloribus non est disputandum)