On the face of it, NightBrightness sounds really cool for those looking for a night mode that changes the way you play...but the problem with this mod is 1) days last a stupid short amount of time. if you're playing on hard mode, you need to be able to do things at night - and the lights in the game don't have enough range to be useful.
2) there's no way to adjust daylight length
so i found this Clockwork mod, and it does everything this mod does, but also let's you adjust day length, and even has some better lighting included with the mod.