Tasting note from here.
The initial taste is light and clean, almost a little thin in the front of the mouth, but then at the back of the mouth and particularly right at the back when you swallow is where this shines, very smooth as the power delivers with hints of honey followed by spice and a rich and warming finish that goes on for ages (and ages).
My favourite of the Balvenie range was always the 15yr Single cask, but that is sadly no longer available. I was less impressed with the Portwood finish (which was also very expensive) and the lower-cost Doublewood, but have now found both the Carribean cask and (16yr) Triple cask to be very enjoyable. Neither are perhaps quite as precise as the 15yr Single cask used to be, but both are very enjoyable.
For previous Balvenie variants comparison, also see here.