George,

Thanks for the update. Looking forward to your expert opinion once you have the board with you.
I heard the demos on the official website. Apart from the expandability(which is a great feature), there seems to be no dramatic improvement in the voice quality compared to say the S550 or even the S500. May be the waverom is still the same as the PSR S500/S550. A few voices and styles added. 64 note polyphony is what it should have been for the entry level arranger workstation.
For someone looking for their first arranger keyboard, this one will be right up at the top of the list.