I don't know any stats, but I do know I had a CF card accidentally flung into a cup of water by someone, and the CF card proceeded to be read by the card reader and images downloaded without problems.
I am looking to buy a CF card as a backup to a microdrive I have, in fact. I have not much experience with the 1GB MD - thus far the one I have has been working flawlessly. The older 340mb cards were problematic - I had one where it would stop writing once a certain amount of files have been written to it, and the worse thing is the camera continues to fire despite the MD going "click click click".
You wouldn't want to drop your MD, on the floor or into water, while your CF would be tougher.