From Yamaha Wiki
The Yamaha MO6/MO8 is a professional level music production synthesizer that comes in two sizes. The MO6 is the 61-key while the MO8 is the 88 weighted key version. The two versions are powered by Yamaha's AWM2 (Advanced Wave Memory 2) tone generator and comes with 175MB of waveform memory, 64 voices of polyphony, over 500 preset programs, over 1700 arpeggio programs, and over 18 different filter types navigated through the 240x64 LCD display.
The Yamaha MO6/MO8's sounds are based on the Yamaha Motif ES sound set which provides for a very complete range of voices from pianos, guitars, and, strings to percussion and special effects.
Among other features, the MO6/MO8 comes with 4 knobs and 4 data sliders allowing you to tweak your sounds in real time. The MO6/MO8 effects processor allows the user to choose from over 190 effects including 116 insertion effects. The MO6/MO8 also has scene capture mode, remote mode, S/PDIF 24 bit 44.1 kHz digital outs, and, two USB ports.