Well, thanks again, I see what you mean, but I'm still messed up. The story went as follows:
I'd been playing TradiJazz for 8 years (with some funk elements if too excited ;-) on my Roland E-piano, using my PSR-740 for Bass&Drums only and I been quite happy. Nothing like recordings and productions. Just home & gigs.
Then all of a sudden I got to know that piano samples in both my KBs are old but not good anymore, so I bought KORG pa500 (judging mostly on price against of Yamaha's) and I'd been happy for another year or so.
Then, after a minute of audition of the Motif piano sound, I felt foolish and deluded and got the XS RACK,.. Another year of paradise. I even started to record with Cubase and I liked it.
Then I suddenly realized that I'd tried to use KORG less and less (apart from the "Nylon" Guitar, it's not bad at all!). Motif B&D have beaten the Korg out step by step. But anyway, I still needed styles to play live!
Then I bought S950, then while waiting for the shipping I heard comparison of the Tyros4 sounds and styles with the S950's and decided to sell just everything to buy the Tyros4.
Then I felt that I would be missing Roland's 88 hammers and Motif SX Arps and maybe Motif piano sound, then I read this thread, then I lost my mood and temper, then what?... "Oh, who you are? Don't pin my arms, please, no straight jacket, I am just a poor musician choosing KB, no..., Medical siren is fading away...)
Sorry for maybe too long history, but I hope that someone here (like a musical doctor.., but a physician, not a psychiatrist yet) will help me to understand what I need really.