I tried all of them, Draw has a handfull of bugs and an ugly GUI.
Phidias is good and more options but it's not as accurate and there's a slight amount of lag when you draw at it's highest resolution.
Colors looks the most promising, it's the only one that is still being developped on and the brush looks nicer which results on cleaner drawings. Also the colorpicking is a lot easier with colors than with phidias.
So my vote goes to colors!