Actually reading my rather rambling last post I may have not helped answer the original question at the top of this thread, but I guess I wanted to stress that rather than any technical feature on a keyboard, a gig stands or falls on the performer's ability to stay "connected" to the crowd by WHATEVER MEANS, and this usually involves a REAL commitment to the audience and what you're doing, rather than skipping a bar in a sequence or... whatever.

There is one other thing I should have mentioned.

I have realised that above all else (and this has been hinted at in previous posts in this thread I know) just about the MOST important thing I can think of in ANY live situation is:

SONG CHOICE.

The right song(s) for the audience.

No matter how obvious THAT sounds, I continually see other acts not reading their audiences, and I'm continually amazed at the dividends paid when we manage to read our audience right.