"FWIW - Here in the U.S. , the JJ's popularity grows by leaps and bounds. "

Really? I'm curious, how did you arrive at that conclusion?
I've only seen two JJ and neither would run up to full power, one shutting down because something let go inside.
If you love tinkering, JJ's for you.
If you want to fly on a regular basis, well, you get the idea.
BRG,
Jon