If I upgrade to Spyder X, where can I expect to see improvements in my display calibration?
This will depend, to some extent, on your displays. In general, the area most readily apparent are more accurate white balance, so your colors don’t have a slight cast towards pink or green, more consistently neutral grays, so black and white images appear neutral all the way from black to white, better control of wide gamut display colors, so saturation of newer display types is more accurately controlled, and more accurate shadow detail, whether this means more open, on some screens, or less open, on others. Remember: extra shadow detail is only a good thing if it is an accurate representation of your file.