Perhaps the "BIG" attraction to Korg (and Ketron) arrangers, especially by the middle eastern market, is because they produce 'oriental versions' of their arrangers. I believe the last Yamaha produced oriental arranger was the PSR OR-700. What makes the 'oriental' arranger unique are it's Arabic drum-kits & Arabic instrument voices, and it's unique on deck 'set of buttons' which allows you to conveniently change the scale tunings.

Interestingly enough, one of my middle eastern musician friends has recently shown me how to turn my Tyros 4 into a middle eastern 'oriental' keyboard by assigning the various middle eastern scale tunings to reg (1-8) and importing custom middle eastern drum-kit sampled instruments. I believe once more middle eastern musicians discover this, they'll be drawn to the Tyros 4 as well. Bottom line, I believe Tyros 4 a most versatile instrument suited to many many styles of music, from music studio production to on stage performance.