The Cree MC-E LED has 4 Independently addressable dies, the P7 does not. you can chose to use only 1 die or a combination of 1 to all 4 making it very easy to select light output levels. The dies can also be connected in series so the driving voltage becomes 14.8 volts, perfect for automotive headlight applications. Also the MC-E at full output produces ~600 Lumen meeting DOT and CE headlight requirements. Technically, it is illegal to use a P7 flashlight at full output (900 lumen's) on any bicycle or vehicle using a highway. This is one reason you do not see manufacturers using P7 LED's in bike lights used for highway use.