I LOVE Pearl Ex! I mix it with Gum Arabic/water and paint it on, spray it on etc.
I also stamp and then apply it with a brush, once dried I use a really soft brush to remove the excess (it is a little harder to completely remove from textured cardstock...I just swish it around and it leaves a shiimmer on the whole paper).
In my experience it works really well on dark colors...
I love to tip/outline dark flowers...real nice!
I'm REAL sure some experts will come along and add some stuff, but thats a start! Have fun