Fiery and hot, even with water, with lots of rye spice. With a bit of water, very rich, long lasting vanilla, a hint of tobacco maybe? Nice sweetness, brown sugar and butter flavor, which contrasts nicely with the vanilla. Kind of like good chocolate chip cookie dough, sans chips, but hot from the rye. It has a luxurious, full mouth feel - it really is buttery.
I'd say drink it really slow, let it rest 10-15 minutes before really digging into it. The flavors open up more with time.
I hit the jackpot with this one. This virtually jumps to the top of my favorite whiskey list, and I know it might be a long time before a bottle like this crosses my path again.