I use efficient plasma on my krait mk2, mostly for PvE , takes down the larger ships wonderfully, not so good against agile small ships as harder to hit.
Long range may be useful i would imagine as long as your enemy is not aware they are under fire.
I would think it would be quite easy to evade shots from greater range. Longer shot time to target etc.
Using efficient i can run 5 plasma - 3 large and 2 medium PA, can manage the power with a OC power plant or guardian power plant.
Heat will be an issue with several PA, as well as the power draw.
Mostly i use them at close range, <500m , rarely miss with practice, leading the target if its moving.
A hit from 5 PA , even efficient is enough to drop Elite Anaconda shields in just over 1 volley. 3-4 good strikes and it is dead.
Tried some friendly PVP with a wingmate with the same setup, was fun dueling to see how good they were.
I run a low heat setup, 17% heat so can be used with a stealth build. If they dont see you approach you can get a killer strike in at close range before they can target you effectively, if they see you at all.