I don't purchase them on my own. I'm part of a small group that selects barrels and we have a fairly specific profile that we look for. We like lots of brown sugar, caramel, vanilla, etc. with low heat. With barrel proof bourbons there will always be alcohol heat, but we try to avoid bourbons that just taste "hot" regardless of alcohol.
The important thing to remember about the Willett bottles is that they are single barrels purchased from KBD (Kentucky Bourbon Distillers). Interestingly, KBD did not, until last year, distill its own bourbon. They have always purchased barrels from other distilleries and age it at their location. Because of this, it's often hard to tell who actually made the bourbon that you're drinking. Also, because they are all single barrels, some bottles could be absolute crap and others could be delicious. The label was made so they could do one off barrels - there is no specific proof or age (these are hand written on the label).
If you have the barrel number of the Willett I'll ask some of my contacts to see if they have any info on the barrel.