I'm with Tom and the KB guys, only because organ is where I started and the early analog synths are where my playing skills really evolved. I have never owned an acoustic piano, and although Im realize it isn't the same, I did have a dedicated electric with similar action ( the Yamaha CP 25 ). I can play an acoustic ok because it seems one way or another I've almost always had access to one , but there is no doubt that I am more expressive on a keyboard / organ because of the way I learned to play. No regrets either. When I was learning to play could have never imagined what was to become possible via midi and electronics. Some of the organs of the day had auto accomp, but there was nothing at that time to compare to what is available today.

AJ