I don't have a sweet spot yet, since I have not had enough opportunity to change the resistance.
On my Tanks (Protanks mainly) with standard coils, they are either 1.8 ohm or 2.2 ohm, but measuring them, they vary quite widely from about 2 ohm to 2.4 ohm. I think I prefer the lower resistance - leads to a more pleasurable vape on VV batteries (Spinner and iTaste VV)
On my Dripper set up (IGO-L with SVD) - I have had 3 coils so far. First one was 1.6 ohm, then 1.7ohm and now 1.4 ohm. Still undecided as to what the best one is, LOL
As result, I have not voted in the vote poll above.
Yeah this scale is wide. Tobacco juices just under 1 ohm. Desert juices a bit lower, and fruity juices a bit higher.
Then as for devices, in ithaka I go around 0.4 - 0.5 ohm. Don't know why, it just works like that. Drippers I tend to keep around 0.8 - 1 ohm, and rocket (kayfun) around 1.2(ish)