What it is: A waterbased makeup that comes in a solid 'cake'.
Availability: Should be readily avaliable at most costume shops.
Setting: Cake is self setting, so after it has dried well, it should be reasonably waterproof. Black less so than other colors. (My theory is that they put less talc in black so that it will stay darker.) White, however, sets up well. In fact, after about a half hour, I was unable to wash it off with just water, even while the black Aquacolor I had used dissolved right off.
Cost: It costs about the same to get a fairly large container of cake as it does a small pot of cream.
Cover: White, especially, may need an extra coat to be opaque.
Pretty decent makeup. It may not come in all the colors you need. It's a little less comfortable and a little less durable than cream, because it dries onto your skin, but it's a reasonable substitute for it. It may be more difficult to blend - I've had some trouble when it dries too quickly, before you have a chance to blend it properly, and the application of too much water may make it run. With a little practice at using it though, it's pretty good. Better than liquid, not quite so good as cream.