I've used it a couple times. In the right conditions, it's very fast stuff. Other times you might as well have left it off. You have to pay attention to humidity and air/snow temperature to know when it's going to be effective.
Since I don't race speed events, it's never been worthwhile to me to make the investment. If I get in some especially wet or heavy snow where traditional fluoro powder and waxes don't cut it, I may apply some Zardoz as a poor-man's MoleculeF, but to be honest in tech races under those conditions I'm more worried about being taken out by a hardened slush pile than if my wax is costing me a tenth.
Let's put it this way- if you're within striking distance of the lead (under a couple tenths) each run and your gear, tuning, and technique are all near perfection, by all means slap it on and see where it takes you. If one of those factors is lacking, you're only applying a bandaid by using expensive overlays.
Hope that helped.