Frank and Elle,
I think you are missing Simons (and The Pro's) very valuable point - arranger keyboards are turn-on, pick a style and go - either at home OR live.

While I for one will not dispute the quality of 'pure' sampling and the ease of use (with a "little work up front") in the studio environment, I can't really see you picking up that computer (plus card, cables, board, mouse, speakers, etc), putting it in an SKB case and showing up at the gig ready to play.

Again I think it's unfair to discuss/compare apples and oranges.

Regards,
Steve