Have the knee pad, cause I also tend to rub the tank with my knees... Nice looking as well... I don't have the top of tank pad though cause it hides the tribal design...
I put them on as mostly-decorative, but I do find my right knee against the pad frequently (probably saving a little scuff on the paint). The left one is purely for decoration and balancing the look. Had them on my '05 America, so I did it again - could have gone either way.