i would not base my decision on a KEYBOARD by its vocal processor,

you can easily buy a dedicated processor which will be better than BOTH that come in either of these keyboards.

you can always change the vocal processor,
but can't change the keyboard, well you can i guess if you wanna spend anothe $3-4 thousand


so if the vocal processor is better on Korg you buy the Korg,
and if better on Audya you buy the Auyda?


go for the keyboard that sounds BEST overall as a keyboard/band, not as a vocal unit, fx etc.

just my recommendation