Blanton's is one of the first modern bourbons to be marketed as a single barrel. With a bit of digging you can find out that despite an official age statement it's usually aged nine years although the official stance is to bottle it when a sample from the barrel says it's ready.
The smell is caramel, leather, oak, sugary cotton candy, with a noticeable but not overpowering alcohol bite. The taste is heavy oak, black pepper spice, a healthy dose of vanilla, and rich nutty toffee. The finish is warming smooth and mellow. Quality and complexity show well in the flavor.
Overall I'd give it an 8/10. About on par with another single barrel favorite of mine called Four Roses Single Barrel. This one's a bit more rich and nutty than the Four Roses. Impressive stuff.