I've never owned a KN6000 before so feature wise you would have to ask someone here who's owned one before. Sound quality is great on both boards, but the KN has great amplification, where as the i30 has no speakers.

imo, the i30 was a very underrated board, not quite sure why that was, because really in terms of sounds & styles, there isnt a huge difference between that and the PA80, if anything, i actually thought the drums sounded slightly better in the i30. if you liked the styles of the PA50, you will actually find many of them in the i30 as well... its touch screen also, but i didnt like the op system interface, wasnt very user friendly, but maybe you'd get on with it...