Have a look at the page describing how those examples were recorded. With the level of care for choosing sounds that people here may use, or with some different combinations of patches the Kurzweil PC3X could sound even better. Especially if some of the effects were used here and there for a subtle boost.

So many of the Kurzweil sounds have been set up with multiple style specific vibrato, delay, reverb and much more. Where on my old Fantom X, I may have had to have several patches lined up in favourites, one patch on the Kurzweil could handle the same in many cases.