Pro: You're absolultely right! 128 note polyphony is definitely a MAJOR reason to upgrade. I don't know how in the world I forgot to include that one at the top of my list.

Btw: The other COOL Tyros feature I forgot to include in my list is the ability for the Tyros auto-accompaniment to actually 'follow' your voice (speeding up or slowing down). This could prove to be a very useful feature as I frequently like to sing the verse of a song in 'rubato' fashion.

OK, now I got 18 reasons to upgrade to the Tyros:

17) 128 note polyphony (Tyros) vs. 64 note polyphony (PSR2000)

18) Tyros has auto accompaniment 'voice follow' capability