I had a KN6000 and traded it on the KN7000. I find the overall sound has been improved quite a bit, they did quite a bit of tweaking to the sound system.
I really like organ and the new organ tabs add a lot to the keyboard, that to me was worth the trade just with that.
I have never heard the Tyros or any of the latest Yamaha keyboards, no one around here seems to carry them.. Since I'm crazy about my Technic's I don't worry about that though.
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Marilyn