@Rodrigo - Regarding Glenfiddich, it's the world’s most awarded and best selling single malt.
And the 15 year (also known as Solera) it's one of my favorites - I highly recommend it! It's matured in three different types of oak cask - first is Oloroso (sherry), then in used American oak (bourbon) and then in new American oak casks. It's much more complex and sweeter than the 12 yo in my opinion. It is impressive and I enjoy it very much.
@Daniel - The Macallan does NOT add any caramel flavoring!
The Macallan 12 year (aka The Macallan Sherry Oak) gets its coloring from the casks used in maturation. These oak casks come from northern Spain and some are seasoned by filling with lighly fermented wine. After a few months, they're emptied and then filled with dry oloroso cherries (yum) for up to 18 months. After that, they're shipped off to The Macallan ; )