I've tried to like BCS, I really have. I think it is a boozy mess. I'm sitting on some 2010 and 2011, that I am going to trade to a buddy of mine. The only one I have really liked was the Vanilla from '11. It seemed much smoother and just jointed (if that makes sense).
I haven't had the opportunity of trying KBS. I will say that most whiskey barrel aged stouts, I just find off. I can appreciate the effort and artistry in aging in a barrel. But they all feel rushed to me. I understand that you should lay these down for some time for a "best" drinking experience, but I would really like to be able to enjoy the product over a course of time from purchase, and I just don't feel like you can do that with these type of beers.
All that said, I do love the base beers for KBS and BCS. They are really well done stouts. Founders Breakfast Stout, just might be one of my all time favorite beers.