I have both the WK-7500, and the WK-7600. The keyboard on the 7500 is very noisy, has a very light, plasticy feel, it feels very cheap (which, of course, it is). Casio has made very noticeable improvements on the 7600's keyboard, it much quieter, has more resistance, feels much more playable than the 7500. Slightly more refined. I hope it lasts.