I don't buy this, either on merit or fact. I grant that many people who sing along with their performances rather than perform instrumentally won't run into the same issues that I do - but on any given song of mine I run drums, bass, guitars and electric piano and/or synth pads with occasional horn stabs or strings as sequenced midi backing or arranger accompaniment. I have used polyphony counters that show this takes anywhere from 30-54 notes of polyphony alone (Yamaha's S-XYG50 softsynth has a polyphony counter if you want to find out the polyphony of your own sequences - free demo at
http://www.yamaha-xg.com). Then on the same instrument I have piano and optional layered strings. Quite often I perform arpeggios with the sustain pedal down, which racks up the polyphony fast with or without accompaniment. The Yamaha 9000 Pro comes with 128 notes of polyphony standard and I can max that out pretty easily (acknowledging that Yamaha uses multi-voice sounds). But to compensate for this I've added a 64-voice dedicated piano card, which solved the problem of running out of polyphony. I also added the DX expansion card to give me another 16 notes of dedicated polyphony (total polyphony: 208). And I did this all for well under what the base price of a PA1-X Pro alone will cost.
Ok, so I'm a power-user and like the option of having more than ample polyphony to cover Yamaha's multi-voice sounds - but at least I had that option with the 9000 Pro... on any Triton-based instrument, including the PA1-X Pro, I wouldn't. The optional Korg expansion cards add sample memory to the instrument but not polyphony. So even if Korg doesn't think it's possible to max out their polyphony and I do it anyway, there's nothing I or Korg can do about it after the fact. And don't even get me started about what will happen when the PA1-X cross-fade dual sequencers come into play. I don't want "least significant allocation", I want to not need it.
Of course I intend to give the PA1-X a fair shot and if it's a better instrument for my needs than my 9000 Pro then I will buy one. I was rooting for Korg in the first place and they came through with things like the first SP/DIF digital output on an arranger. But the polyphony issue isn't going away without solid hands-on evidence that it isn't an issue - and if Korg's production costs to match the polyphony options of Yamaha's 9000 Pro are too cost prohibitive for them, then that'll be all the more reason to stay with a proven leader.