Up front, I must say that I am currently a Korg dealer, and a previous Kurzweil dealer.
The stories and suggestions about the problems with the PC-88 are true. Kurzweil (Young Chang) has had major problems with the PC-88 for a number of years (it's by no means a recent model). The major problem with the unit seems to be a lack of torsional rigidity. That is, the case twists too much. Most of the problems people have with the PC-88 come from moving it around. The stress on the long circuit boards from movin the unit cause connectors to become intermittent, and this causes software problems (random crashing).
As to the QS 8.1, I've not been overly impressed with the percussion sounds. Maybe its because I've owned Korg boards for years.
Steve Martin
Ward Music Ltd.