I too, am a fan of vocal harmonizers and have used them for over 10 years to get my "trademark" vocal group sound. It is the first priority in my shows, followed by the bass&drums, then all the other goodies. As long as the voice, bass & drums are good - I'll handle ANY crowd - even with a substandard keyboard. With THAT said:
I have been disapointed by ALL the built in harmonizers that come standard in the top arranger keyboards. I've had them all too:
Kn5000,Psr9000,X1,G7 - none of them gave me what I needed. Now granted - I'm extra fussy about my vocals and I need to be able to manipulate in and out of the harmonies with the ease of a cat on the prowl. My foot is alsways poised at the on/off switch for the harmonies. I admit that the convienience of having a unit built into the keyboard is nice - but NOT at the expense of functionality. I can put on a better show with my digitech unit than with any of the other "built-in" units. This is largely because I trigger the chords from my RIGHT hand and i need it to follow every little change. The X1 was erratic, although very good sounding, the 9000 was poor in response time, and the Kn5000.......well that was just crap. The mic input is terrible on that keyboard. I am really hoping that the new Korg has a better than average harmoniser in it, because I would love to be able to "free up" that space in my rack. As it stands, I only need three spaces to cover my whole rig with tremendous flexibility. I use a three space padded bag that hangs vertically from the front two arms of my IQ2000 "X" stand.
top space igitech Vocalist access
middle: Sony E10 mini disk player/recorder
bottom: Toa D3 mixer (4 strereo channels)
So far it's a perfect fit, but I am always looking to simplify my life in transit
If your vocals are truly a priority, as they are with me - don't settle for less than what "you need to hear" just to save a few wires or pounds. I remember a few short years ago......it used to take me twice as long to set up; just to sound HALF as good!