Something to know about Foreflight is that it only works with one ADS-B (I believe it is), and the iFly works with a different set of ADS-B units. So you can't run the same ADS-B on both of those programs (aps, whatever they call them now). At least not at the moment. That's from memory, so somebody's welcome to "clarify" that if I'm wrong...
Mark Langford ML at N56ML.com http://www.n56ml.com