Conformal coating is a thin almost runner-up layer that is put on the PCB boards (electronics) to help protect them from various weather related elements.
As for a the J model and dual flash models being the almost the same....the original flash modules are for both IR and black flash, but the dual flash allows you to upgraded to powerhouse modules, an errr e as the J series does not. As far as battery life, when I called cuddeback I was told that the dual flash you could expect twice the battery life as compared to the J series model. Also, the dual flash model has a battery booster pack and that currently isn't one for the J series model. I believe in the further the dual flash module will be more upgrade friendly, so that's what made my decision. Its an extra $250.00 upfront for a set of 4, but if I can upgrade four cameras to the powerhouse for 50.00 each ($200.00),as opposed to having to buy 4 new cameras ($750.00) if the come out with brighter flash modules for the J series cameras.