I'll pop open a bottle and think "This is incredible!" then a few days later I'll be looking forward to enjoying some more, and be severely disappointed. OWA did this to me, though I still enjoy it overall. JBB really was the monster though. First pour was very sweet but not much else, but the sweetness made it interesting. The rest of the pours lost all the sweetness and left only bitter wood with no other flavor at all.
Then other times, the opposite will happen, where opening a bottle and getting some fresh air in there seems to 'open up' the flavor a bit (seems to be the case with EC12 for me).
I do agree about KC --- great, reasonably priced, readily available, consistent stuff.