David Carradine also speaks very highly of Marc's work on "Kung Fu." His comments are included in some of the bonus features on the DVD's. If memory serves, David said that Marc come in and shot four of the last five episodes of the original "Kung Fu" back-to-back. That was unheard of the 1970's and would never happen today.
I'm not sure if David Carradine's memory is correct, as apparently Marc had a heart attack at one point while filming those last episodes and had to sit out a while.