I had a bottle of Ben Nevis from Cadenhead's. It was cask strength and around 12 or 13 years old - I really can't remember the exact bottling but it was bought about a year ago. It was thick, dark and like an old, sherry steeped fruitcake. Very rich. It did have something on the finish that I can't quite describe - some kind of dirty dryness, rather bitter despite the sweet taste of the whisky. I could never quite decide whether I liked this aspect or not. But tons of flavour for your money. I would certainly consider getting Ben Nevis again.
Sorry for the inexpert notes - if you want class, go to Jim Murray.