Here is my 2 cents, The T5 and Audya are completely 2 different animals and 2 different age groups.

I also think that the boards are tailored to different audiences, even though it can be adapted.

I always found the yamahas to be a more of a Americanized board with touching on some latin and world styles. I owned various yamahas and they were great for one type of genre but not another.

I think the ketrons are geared for european and latin american play, that also adapts to the american genre.

Yamaha has never been known for their latin. Their latin genre can suit a besame mucho or a cha cha cha at a retirement party, but will never compete with the true south american latin styles of a ketron and Italian styles. Also aj's adaption of African styles just opened up another market of players that other keyboards do not have.