If you like feeling claustrophobic or want a horror experience (in which this mod delivers greatly, gives so some great scary moments) then this is the mod for you, but if you want realism, then it might not be the best mod for you.
You don't have to pick the darkest one, there's 7 different files to choose from. I think #4 is a good balance.
I was going to say this, there are multiple choices to pick (4 being a good balance as pointed out).
I like the darkest and use the Legendary Lamps mod: http://www.nexusmods.com/fallout4/mods/1707/?