So I've got the Challenger with V7.0 board to see how much improvement there has been since 2005. What I learnt with that I can maybe apply to the others.
One area I'm desperate to get up to speed on is FPV. The last one I tried to cobble together in 2005 was a bit disappointing, a tiny CRT TV, with an extruded aluminium receiver hanging out the back of it, plus a little Chinese sugar cube cam.