QC doesn't have a specified age. People think it may be 8 years, but the 10 year is all 10 year. Sort of like the difference between a vintage and non-vintage bottle of champagne. I think also the QC is a blend. I don't think so. QC is a SM that is aged in smaller barrels. This means that relative to the volume more whisky is in contact with more wood...surface area. It simply ages faster than whisky in larger barrels. Personally, I think QC stands head and shoulders above the 10--Ilike peat and Islay malts almost to the exclusion of all others but that said, I value drinkability as well and am not into rough or harsh simply for their own sake.