Korgs have always sounded way more live than Yamaha which sound more like a CD, (Just do a search on the many forums out there) with most Yamaha owners heading straight for the EQ as soon as they get them (Korg owners less so).

As I am regularly out listening to live music this is what I base my comparisons on, and after hearing and trying both the PA4x & T5 I personally would go with the PA4x any day of the week. (The Yamaha Classical/Theatre organ bank is better than the PA4x as are the ensemble voices, plus Yamaha have refined the SA voices to perfection, however avoid the SA2 voices as they are totally unrealistic, also Yamaha styles fall well short of a live band feel, but there are so many free ones out there you will probably find something you like)

As each person is different only you can decide which is for you, so go out and try them and take online demos with a pinch of salt.

Bill