Nigel Cheffers-Heard on this Flickr thread commented (my headings)
"The autofocus is leisurely to say the least, and for candid photography is a nonstarter (by the time it has locked on, the subject has seen you and the moment has passed).
"One alternative is to have the camera set in Manual Focus, and to momentarily press the AFL button to achieve focus. Frankly, too fiddly and time wasting. And the gearing! But more of that anon...
Another alternative is to set the focusing distance manually using the focusing ring and the scale on the rear screen. Sadly, the implementation of this is nothing short of disastrous. The actual linking between the focusing ring and the lens focus travel is electronic. So presumably you can have any “gearing" you choose to program in. For reasons best known to themselves, Fuji have programmed this so that to focus from infinity to minimum focus takes three complete turns of the focusing ring. Three turns!
I have to ask if they let any serious photojournalists used this camera during the alpha testing phase, because I cannot be alone in thinking this is not a good decision."
Street photographer John Goldsmith has written a detailed review on Street Reverb Magazine, and has similar misgivings (my headings):
"the autofocus is reasonably fast though not nearly as quick as my 5DMkII, even in great light. In short, I didn’t find the autofocus performance fast enough. In the case of the X100, the freezing EVF, the lack of a focus tool in the OVF, and the relatively slow autofocus, don’t leave any quick and reliable focusing options for speedily composing a street photograph. ...
"This focus ring, which seems to have been dipped in high-grade honey, can take as much as 5 full rotations to move to the opposite end of the scale. Fortunately, if I understand the mechanisms of the camera, the focus is electronic, or fly-by-wire, and this suggests that a firmware update could be an easy fix."