@ Koji,
Devlan mud is great for clothes. The minis not your own! The Army Painter dip is a shader and a gloss so you would need to either paint over with a highlight or use anti shine gloss spray on the top. The dip really is best for speed if you haven't got time to sit there with a brush to paint say 50 Goblins before next week.
It's great for getting the armies on the table quickly but you are not going to win any golden demon from using it so don't use it on minis that you are sensitive about making look super pretty. It's great for shading rear ranks of units. Have the best painted models in the first and second ranks and then have the rear ones base coated and dipped. I think the Primers you are interested in work well with the dip. As I said though if you just dip the basic colours and then go back and add some highlights it works well for depth of field.
Here's some videos about it:
http://www.youtube.com/watch?v=FttcUrV4j-g&feature=fvsr
Also I can show you the difference between a dipped with added highlights and non dipped here, the one on the left has been dipped on the skin coat and then other colours added, the one on the right has no dip but two or three highlights.
Next the three guys in front are without dip the guys behind were all dipped yesterday with further colours added.
Here is the unit as a whole with the undipped at the front left and the dipped to the rear right of the ranks.
For an intermediate level painter like me there is not much in it. The dipped ones are more shiny but that will fade over time and at least it will be well protected.

Forget about yesterday, don't worry about tomorrow because all that matters is today.
Minis painted in 2017: 13
Minis painted in 2018: 45