Thanks Nickynooch - I never considered there could be a mapping issue - I'll have to try it out.
My full-size cab will use U360's so I'd be curious to know why you're using xpadder.
My bartop CP is simple: 2 Joysticks, 4 buttons each, P1, P2, Pause button (mapped to P), Exit (mapped to ESC), C1, C2, and ENTER (hooked up to an iPac). Oh and I've left & right flipper buttons for pinball.
Ideally - I want the Exit button to be used to Quit whichever game to return to the FE, and to Quit & shutdown the cab when in the FE.
That said and assuming I understand you correctly - if I switch my EXIT button from being mapped to ESC to END that should solve my problems? Wouldn't that cause issue in MAME & Daphne? Both use ESC to quit the game.
Be seeing you,
WonderAlex
PS: Just to be clear, I'm not saying that MA is bad - on the contrary I think it's very good - quite possibly the most stable FE I've tried so far (it hasn't crashed on me once). It will likely be my second FE once I can sort out a few things (namely the VP9, and my own customized theme).
And of course I agree - every FE has "issues" - MA is not immune, neither is AtomicFE, Mala and HyperSpin - the other FEs I've been heavily testing. AtomicFE took me a long time to get just right and I expect no less from MA.

** Edited to add PostScript