I used a Canon 50D, EF 70-200 f/2.8 L IS and an EF 2x ii.
Exposing for 2 seconds or more was enough to for the moon's movement to blur the photo. With the EF-2x on, apertures wider than F/8 didn't seem sharp enough. ISOs above 800 seemed to lose too much detail to noise. I only used IS while focusing in live view. And a cable release and mirror lock up seemed to help.