Admiral, I've not tried the 12 year old Caol Ila
yet, only the 18. I would imagine that the 12 more powerful as per the Laphroaig 10 & 15, the Lagavulin 12 & 16 etc etc.
Diageo only brought in the 18 (I'm glad to have that) and I think it is a really fine whisky from a distillery that people are too ready to write of as a makers of whisky for blends only. I've add some stunners from the SMWS. I liked the 18 so much I went and bought a back up bottle because there is so little of it around.
As an aside Diageo has been bringing in small lots from various distilleries, like Caol Ila, and once the supplies are gone they will not be replaced. It seems they're trying to satisfy the collector/malt lover market without expanding the normal product line up (classic malts etc).