My vote for best professional organization in the defense/aerospace industry: the Society of Experimental Test Pilots.
And it's not just because they can get Neil Armstrong (Neil Armstrong!!!) to come to their annual symposium in Disneyland next month and brief attendees like me on the lunar vehicle test program (although, honestly, how do you top THAT?).
It's also because it's the only event on the aerospace convention calendar where virtually all the briefers make news, at least for a rumpled, ink-stained, trade wag like me.
Consider this abstract on a panel of speakers talking about the Small Diameter Bomb program:
"Unfortunately, the transition to the F-22 from F-15E is not as straightforward as it may appear. Many testing challenges, some of which have yet to be overcome, have arisen in the physical integration, instrumentation (specifically in loads measurements), range availability/clearance, and limited lifetimes of both the flight termination system (FTS) battery and weapon battery"
Remember, Small Diameter Bomb is the weapon that justifies the F-22 as a multi-role fighter.