I'm speaking now as a Kentucky Colonel, with my father having been born in the commonwealth. Kentucky bourbon is in our blood, and I think between us we've tried them all.
The hands-down best, in my opinion, is a little-known brand called Rebel Yell. It holds the top spot formerly held by I.W. Harper, the maker of which decided to start sending nearly 100% of their output to Japan. The people there are willing to pay through the nose for it. I still have a quarter-bottle of it, inherited from my father. It must be 40 years old.
I was introduced to Rebel Yell by a bourbon aficionado who sent me a prized bottle of it for my birthday many years ago. He has since passed on, but I will always be grateful to him. Rebel Yell is so very, very, smooth and flavorful. I order it by mail from a distributor in Los Angeles; I believe it's one of the few sources. It's pure Bourbon nectar.
I must remind some people that Jack Daniels and Gentleman Jack, while they are fine whiskeys, are not bourbons. These are often referred to as Tennessee Whiskey or American Whiskey. Real bourbon comes from Kentucky, and nowhere else.
John