Hi, I perform with the Yamaha PSR 3000 and the Korg PA 60....is a nice combination, you have a great sound/style pallete and since I am a former organist, I am used to play with 2 keyboards anyway,
I also did use the Ketron SD1 for over 4 years, I still miss the great sound generation even is "old" to the todays technology, but for live quick performance, is a little slower that the 3000 or even the PA60. Poliphony in 3000 is great, and the PA has it limited but with the best dynamic alocation, the SD1 once in a while would give me a little problem that way.
Like I said before, great sound generation the best MIDI files playback (better that either of the boards I own)...but I rarely use SMFs....so, that's why I use these models & brands.