[jfrancho]

There are many ways to skin a cat in Photoshop, and I suggest you try them all before ruling that one way is superior to the other. By using color mode, you are shifting the gray point (regardless of which dropper you use) to achieve a color correction only. By using normal mode, you are eliminating wasted color depth by stretching the histo across the range, and using the middle dropper to affect and resolve any color shift caused by such change in luminosity. Two birds, two stones. YMMV - you won't know until you try. Each image has its own limitation.