I did some tests of these two camera / lens combinations and also took them out together to see what they came up with.
Below are a series of tests of the different cameras taking the same picture. If you click through to flickr there are larger sizes available.
In terms of results I prefer the Fuji every time. They are sharper, less noisy and I prefer the "punchier" colour.
Its not as though the Olympus / Zeiss combination is bad, thats certainly not the case, its much more about how good the Fuji X100 results are. Really very impressive indeed, yet again. If Fuji ever decide to come up with an interchangeable lens version of the X100, with the optical viewfinder adjusting to the different lenses then, assuming those lenses are the same quality, it could prove to be the ultimate Compact System Camera.
By the end of my "test" outing, I decided to use the Fuji exclusively, as I was missing shots by manually focusing the Zeiss. I decided to make the images black and white as it suited the content and the light.
So the X100 proves just how good it is yet again. I think the Olympus / Zeiss combination still wins the beauty contest though!!