Colour: The 2012 and the 2016 have the same colour of old gold (of course, as they still use caramel to achieve this) while the 2013 is three shades darker at amontillad. The texture of all three drams is very similar with some early slow legs and many late fat and sticky tears.
Nose: The 2012 offers a rich and complex fruity and phenolic nose with some OBFs (lacquer paint) right from the beginning. The 2013 is quite comparable with phenols and some OBFs too beside the nice sugary and wooden aromas. Contrary to this the 2016's nose is rather shy on mainly peaty and herbal aromas that take quite a while to enfold. No OBFs here. After adding some water the 2016 opens up and shows now the yearned OBFs, finally. The 2012 and 2013 are significantly better on this dimension when neat and still slightly better with water. I like the 2013 best here.
Mouthfeel: The 2016 arrives warming and coating on the palate with no distracting moments, really nice. Same with the other two but the 2012 is a little astringent (tannins). Here I like the 2016 best closely followed by the 2013.
Taste: The 2012 is nicely layered on sweet (honey and different sugars), peaty and spicy (peppers, nutmegs, salt) flavours all in perfect harmony. The 2013 is again comparable with some additional chocolatey flavours. Obviously they added some (more) sherry casks to this batch (hence the darker colour). The 2016 is somewhat shy, less sweeter and more phenolic. But complex and layered too, after some chewing it shows a lot of nice additional aromas (floral, herbal, some fruits). All are quite different on the palate but each is great in its own way. Finally I like the 2016 slightly better and the other two are a draw.
Finish: All are very long and vanish slowly in waves. No one shows any bitter or drying moments with the 2012 being sweeter and more spicy (peppery). The 2013 is sweet but less spicy and more chocolatey again. The 2016 finish is more complex than the other two on herbs and autumn floral notes. Here it is a draw between the 2012 and 2016 while the 2013 is slightly weaker (nevertheless on a high level).
The 2016 is an excellent swimmer and improves significantly on some water, especially in the nose. On the 2012 and 2013 water is not needed but does no harm either (it releases more fruits in the nose) - so I advice to try it both ways.
These are three great drams at a still very reasonable price (compare the 135-150 Euro here to the price of a 25 year old Lagavulin that - by the way - I scored with 89 resp. 84 points only). As a drinker I prefer any of these Caol Ila over any of the same aged Lagavulin. These Caol Ila are (still) a good deal to buy, given you like this profile...