if you go to a national MX race, all the pros have been running these for a few years and it trickles down to most of the A class guys and some B class as well. what i was told was instead of just an on/off type application of the front brakes, these do a much better job of modulating the amount of braking at incremental lever positions. Not sure if true or what the point would be since the later and harder you brake the faster your lap times.
aka "Jumps for show, corners for dough"
I've been tempted to buy one, but havent pulled the trigger. I believe both Wienen racing and hetrick racing are dealers and have suggestions of which options to use.