Most people that sing THROUGH the arranger will tell you the Yamaha's harmonizer is WAY inferior to the Korg's.

Just in case you were considering using it on ANY music...

And worrying about whether a built in mp3 recorder is any good or not is kind of moot in these days of SD card pocket audio recorders at under $200 that can record at 24bit 96kHz if you want it. AND offer lots of other possibilities (got to have the arranger with you if you want to record ANYTHING, throw the pocket recorder in your pocket to use it anywhere!). If you want to make a decent CD, HAVING to record in MP3 format first is already one strike against it... JMO.

I think something I said originally got lost, along the way. "ALL THINGS BEING EQUAL" the arranger that allows you to play your ethnic music better AS WELL as cover the other bases might be the choice to look at. The new Korg's are very well respected here, and may, even for the main kind of music you play, work out just as well as a Yamaha. Add in the fact that they CAN play the ethnic music, and the Yamaha's can't (or do it poorly, at least) and the equation might look differently.

Just a thought...

I guess, though, my main advice always stands... Don't listen to us HERE. Go listen to the arrangers THERE... Make your OWN mind up!