Here's something from the Mass Quantities site about creatine.
Mass Quantities uses pure, pharmaceutical-grade, micronized Creatine Monohydrate to create Volumex. Micronized means that Volumex is manufactured with a 200-mesh screen, leaving the material a fine powder. How does this affect creatine? The best way to benefit from any nutritional supplement is to achieve full absorption of the ingredients. Because Volumex is broken down into smaller, finer particles it suspends in solution for much longer than other creatine -- mixing instantly and absorbing quicker into the system.
Whatever you do, don't waste your money on "effervescent" creatine, "liquid" creatine, or creatine "transport." These products contain very little actual creatine monohydrate and lots of sugar. If you want to take volumex with a sweet drink like Kool Aid, go ahead, but when selecting creatine, what you really need to look for is that it is HPLC tested by an Independent Laboratory and that is is micronized to a 200 mesh (the finest mesh possible).
The reason micronization is so important is that it allows allows more creatine to enter your blood stream and finally your muscles. You probably have seen how regular creatine settles quickly in a glass of liquid and likewise in your stomach. This is the reason some creatine causes irritation and intestinal distress. Volumex remains suspended in liquid which dramatically enhances absorption.
Here is a complete article on it.
http://shop.massquantities.com/supplements/108.html