"......Before you get excited, think. Do you have any Korg PA series after PA80/60/50? If you do, skip......"

As a matter of fact I have just purchased a Korg PA50sd to sit on top of my Ketron SD7, quite an impressive combination and on the cheap as the ketron was a secondhand as well....
Could not agree more about the Triton engine and the Korg arrangers starting with the PA1X. In those days I programmed very extensively for all of those models ( PA1X, PA 50/60/80/KMA) and I still have all of the goodies for those interested.
The PA50sd has the added advantage of the sd card slot whereas the sounds and styles are virtually identical to the PA1X.
Programmibility is most extensive and very deep and as a second board it is to be preferred imho to these new ducklings of Korg....

regards
John