I agree with Frank and Fran. The 9K Pro is a great KB, but not very good for playing back midi files, since it uses the XG sounds and not the panel sounds, which are much better.
I'm not very impressed with the XG sounds at all, compared to the panel sounds. In order to make midi files sound good you have to go through them, revoice them, change volume and maybe DSP settings. I love my Pro, but I wouldn't buy one to play back midi files. I hope Yamaha will come up with a better solution in the future.
Otherwise the board rocks (if tweeked a bit and shown who the master is).
Eric