There are many reviews on this so mine is rather redundant. More of a personal note then.

Had in a lineup that included: Laphroaig 10 CS (8), Cairdeas 2016, Kilchoman 10 yr first fill bourbon, 1983 Caol Ila 29 yr hoggie. There may have been another, but what was glaring in this lineup was the absence of wood influence on the Lagavulin. I never really understood the appeal before it was put in this context. I found it was closer in many ways to a very naked Dailuaine (108496), than the other Islanders. You get a sense of the wort, and new make. ‘Pristine’, ‘milimetric’, ‘like a blade’...just read Serge or Angus, they describe it perfectly. It’s completely transparent. I get it now.

https://www.whiskynotes.be/2017/lagavulin/lagavulin-12-years-2017/

Nose: sweet, deeply sooty, with lots of medicinal notes, coastal notes, shells on a beach, putty and earthy notes. As expected. Some gherkins, but there’s a gentler side too, something of butter pastry, almond cream and lemon oil. Sharp and powerful, but somehow very balanced.
Mouth: same intensity. Big peat with pepper and lemon. Smoked fish, leathery notes, ashes, wax and salted caramel. Medicinal and very coastal. Just a few fruity notes in the background. Big, big sooty notes.
Finish: very long, ashy, lemony. Perfect sharpness.Pretty much a benchmark for this medicinal, robust, hugely sooty style. I often had problems with its fierceness and dryness but for me this is slightly sweeter, more balanced and the most enjoyable batch I’ve had. Recommended. 

This powerful malt can handle a teaspoon of water to a nice dram, then it is even fruity, without losing substance, clarity or smoke.

Not as good as 2016 but better than anything thereafter. Yes, I've tasted them all up through 2020. In fact I have tasted every lag 12 since 2012 and some before that. On another subject, I just adored the Lag DE 2012. Such a good one. It had notes of bbq'd salmon!