For image editing Im used to set values for low, middle and high lights - which is represented by the histogram plugin in Cin.
Which one is better? The one at Color_Correction or the FFMpeg one?
Ive never used ffmpegs histogram so I cant tell you. The Histogram Bezier plugin also has curves. To work on the Low, Middle and High tones zones you can also use Color3way, which is easy and convenient to use.