Frank,
It will come down to ease of use vs. cutting edge sounds. I believe the SD1 has a slight edge in the sound dept, but the operating system is way behind the brilliant simplicity of the 9kpro. In addition to simplicity, Yamaha has added some "spice" that the SD1 doesnot have - music finder, OTS, multi pads (correct me if I'm wrong .... SD1 does not have those)
The drum patterns on the 9k are simpler, yes - but SOOO musical and logical in progression. I appreciate the Q&A session, but these two kb's are so expensive - you really NEED to have alot of hands on time to make this desision. I was pre-sold on the SD1 in the store, and after the first set on the job .... I put it right back in the box. I could tell that it would not work well for me. Take a trip wherever you need to, but play the heck out of them both first.

George - I don't think you are biased in ANY way ! YOu like what you like (just like all of us) but you tell it like it is when asked. An informed preference is NOT bias. Keep up the good work!