"A poor man's f.lux" is a good way to describe Shady.
A hotkeyable screen brightness preset might be useful to some, but I prefer the greater capability of f.lux if you want to manage screen glare.
I use this frequently — it's a terrible app that's pretty useful. It doesn't support Retina screens very well, doesn't work on secondary displays/full screen apps, and hides every time you open something like Mission Control, flashing the bright screen into your eyes. It can be useful though.
Equidam
Indistractable
Watershed
Copyfeed for Mac