The korg pa700 has a touch screen, functionality not available on the psr s775. As for its sound library, the korg pa700 wins the battle with about 1,700 factory sounds, Oriental varieties and 106 drum kits versus the yamaha psr s775 with its 1,410 sounds (930 main sounds and 480 voices xg) and 50 drum kits.
... And more
ideal for church, studio, bands, etc