GW series sounds pretty good to me if you know how to record a KB demo & most of all know how to play an arranger.
http://www.youtube.com/watch?v=ndPwCTxKUgI

Also....Roland have done nice ones in the past with the Gw7.......... as these....http://www.youtube.com/watch?v=T5H8_6WgwgY&feature=related
http://www.youtube.com/watch?v=fxBwUWB0YTA
http://www.youtube.com/watch?v=pG5FIfkxSGk&feature=related http://www.youtube.com/watch?v=CqaYzpDnuIE&feature=related