I really love using Starblends for background colors. It's much quicker for me than sponging. I only use mine dry. It's also the most "cost-effective" of the powders when doing a LOT of face painting.
When I do "older" youth or adults with more sophisticated designs, I prefer using my Ben Nye Luminiere powders. They're much more rich and shimmery but cost a lot more and come in a little container.
It helps if you take the opposite end of your smoothie-blender (the hard handle) and gently scrape some of the starblend loose which will allow you to pick-up a little more to lay on the skin.
Marcella has a GREAT DVD on using the powders which helped me a lot.
Good luck!
Sparky
LAFS For Life
ACTS Entertainment
ACTSClownMinistry.org