I noticed the same thing today, but didn't really think anything of it until you mentioned it now. For those who don't know, LedEngin has multiple "bins" for each part, and some are better than others. Much like how intel used to use the inferior pentium dies to make celeron processors(or at least so the rumor was).

Multi die comes back to weather it is better to focus more light in one area or spread it out. With LED the advantage will be for situations like SCROG, where you can place the lights very close to the plant. In that case its really price as the limiting factor - how much are you willing to spend per light. If you could have an 8sqft array with all LedEngin multi die leds, that would be ideal. Then your limiting factor would be more about heat dissipation than anything else.

Has anyone tried a cluster type lighting system? Where you would have small clusters of n LEDs and then strategically placed in nodes around the SCROG. My thinking here is that the plants would cluster around points of light and be easier to manage when the screen is removed. I was thinking each cluster would be around 30 watts of leds (80% RED and 20% BLUE?). This would make the ATX power supply really easy to implement, and would solve some of the cooling issues by spreading out the heat.