I am impressed by

1) all the buttons and sliders on the board
2) the great vocalizer
3) the speaker system
4) the addition of auto-fill
5) pitch correction
6) piano and acoustic guitar voices

If I were in the market for a TOTL arranger, I would still probably go with the T4 because Yamaha has more styles that take advantage of auto-fill. I say probably, because I would love to get the opportunity to play the PA3X.