Booker's is the only indiluted, unfiltered, straight-from-the-barrel bourbon available. All other bourbons are diluted down to 80 proof or so before bottling. This particular bottle of Booker's is 127 proof! And it has a number of interesting effects.
First, the attack. When you sip it, your tongue and lips go numb. That's the alcohol talking, boy. All you feel is warmth and a tingle. Then the nose hits, and it's as powerful as any whiskey I've ever tried, including really peaty scotch. Burnt sugar leads the way, followed by anise and fennel seed flavors, lavender... it's reminiscent of herbs de Provence, if someone set it on fire and then tried to put the fire out with some orange juice. Very, very impressive.
About a shot's worth later, I'm finding myself awfully buzzed to be writing criticism on the intarweb.
I'm going to give it another try soon, on ice and with some spring water, to see what works best. I'm afraid of diluting it and taking away that furious punch-in-the-face attack, but I want to see what happens if it opens up a bit.
Anyway, it's an interesting and unusual take on bourbon, and certainly got past my anti-bourbon prejudices.