I think that Yamaha releasing the S975... looks like the company made a BIG mistake with the S970. It is just a lot of corrections that could have been done with firmware except for the increase in expansion memory. Why buy another whole keyboard for a few fixes.
I would not buy the S975 having just bought the S970. Like others... I'll wait for the next S9xx replacement. We know that these fixes will be on the next PSR arranger and probably a few more enhancements as well.
Joe H