Before I sell my Pa500 today I made some comparison tests using same styles (taken from pa500 and loaded on pa3x). I only adjusted higher the volume on the Pa500. Master EQ off on both arrangers

Styles
http://soundcloud.com/vgrodek/pa3x-test-standard-beat
http://soundcloud.com/vgrodek/pa500-test-standard-beat
http://soundcloud.com/vgrodek/pa3x-test-easy-listening/s-tdvEy
http://soundcloud.com/vgrodek/pa500test-easy-listening

Sounds (always played on Pa3x first)
http://soundcloud.com/vgrodek/pa3x-pa500-one-on-one-compare
http://soundcloud.com/vgrodek/pa3x-pa500-harmonica-compare
http://soundcloud.com/vgrodek/pa3x-pa500-compare-nylon-slide
http://soundcloud.com/vgrodek/pa3x-pa500-wide-strings-patch

PS Sorry I can't solve the background noise problem coming from my PC.