Although I don't doubt that Carmack said he specifically wants the game to run at 60fps... I saw juttering in the video. I usually have an eye for it, and can't stand watching movies at 24fps on a 60hz display.
(I have frame interpolation software on my PC so that all films I watch in MPC have the same effect as a pristine 120hz/240hz display)
Then again, my eyes could have failed me this time.