I don't own the MZX-500 but Casio did little to promote it when it came out compared with the PX5S where all kinds of videos were made to teach users how to use them. Take a look on Youtube and see all the videos for the PX5S made by Casio. Casio seemed to abandon the MZX line after fixing some issues through firmware updates. Then the availability started to dry up in select markets for unknown reasons as vendors stopped carrying them and Casio stopped stocking them. They remained available in North America but they are now discontinued there as well. So it seems it was not a successful product for Casio as far as sales and must not have met expectations. But Casio has never been a big force in the pro market. They have served the home market and have been successful making low cost products with a lot of functionality for the price. They seem to have gone back to this strategy as evidenced by the CTX line, Privia PXS, CDPS and Casiotone CT-S. The MZX was supposed to compete with the PSR-S and Korg PA series. I would think the CTX line will be refreshed or enhanced and perhaps the XWP1 might be replaced.