They are different animals, Bill. The 16 is 43% and the 8 is 48% which makes a difference in the drinking. The 8 has a lot more of the bourbon cask maturation while the 16 has a bit more sherry maturation. The youth on the 8 brings in more peat and smoke than the 16 and it's less sweet as well being a bit rougher. The 8 is something kinda in-between a Lagavulin 16 and an Ardbeg 10, although it is less earthy than the Ardbeg 10.
When the Lagavulin 16 was only $10 to $15 more expensive than the 8, it was hard too go with the younger one. Now that the 16 has shot up in price, the 8 sounds more appealing.
But again, very different takes on Lagavulin but both are very enjoyable to me.