"The Face" did have some good lines in it but so did "Fear Nothing" and "Seize the Night". "Odd Thomas" wasn't to bad, it had it's moments. Koontz to me, Liam, is like you said, sometimes his humor does seem forced but a lot of the time he has some really good lines.
King, on the other hand, I see as a smart a$$, he could just come back and hit you with something when you least expect it. Class clown? He seems that way but I didn't catch that he was in "On Writing". His brother, Dave, was though.
Has anybody read King's son's book yet?