You said it best when you wrote:
A PSR3000 owner will never be satisfied with the instrument as a substitute for a piano.
A PX400 owner will never be satisfied with the instrument as an arranger keyboard.
I'm on that page too with what you said. When I looked at the PSR it just was too small a keyboard, since my music background was with piano. But the Casio just doesn't have the accompainment that I want and have come to depend on playing most gigs. Still not sure what I'm going to buy but am in the market for either a PSR 3000 or a Roland G70. I've mentioned in other posts that what I'm looking for I already have at home the Yamaha cvp107, but it's just not portable.