Hi
It seems the AF speed of the XPro-1 is possibly quite similar to the X100 (i.e., not fantastic), and while I understand that this is a concern, I have found that in reality, it has worked quite well for me.
I bought my X100 in early December after fighting the temptation for months (mostly due to the various reviews calling out its various perceived flaws) and found out to my pleasant surprise, that even though the various reviews are mostly accurate, I was able to adapt and overcome the various shortcomings of the camera to the extent I've relegated my D700 + 35mm lens to the dry case far too often in favor of bringing out the X100.
It's true the AF speed is slow, and it's almost hopeless tracking a moving subject, but these are not things I do with my Leica M6 in the past too. With a traditional rangefinder, I would preset the focus distance, or prefocus and wait for the decisive moment to occur, or for subjects to walk into my frame (again, a feature of the window finder you will not find in a SLR), and I was able to continue observing the subject even after the moment of exposure for more possible pictures because I experienced no viewfinder blackout with the clear window viewfinder of the M6.
I was able to inherit this very valuable shooting experience entirely to my X100. Yes, the focus is slow like molasses compared to my D700, and sometimes not accurate, but it has a wonderful distance scale in the finder, and with the X100 set to manual focus, one press of the AFL button will activate the auto focus system of the camera to my selected distance or subject, and thereafter it's a matter of releasing the shutter at the right time while observing the subject through the window viewfinder.
It is foolhardy to try to follow focus a moving subject with the Leica M rangefinder, and it's the same with trying to AF on a moving target. For me, my best pictures were never a result of me seeing a subject, and rushing the camera to my eye while auto-focusing at the same time to shoot. My best pictures come when I observe a scene, select the background, choose a focus point and let the action come to me, releasing the shutter until the definite moment.
Actually, I do the same thing above even with the fast focusing demon that is the D700....
What I love about my X100 is that it brings to my mind so vividly the experience of shooting with a film rangefinder, and it offers advantages that a SLR does not.
I regretted waiting so long to get one due to the negative press and reviews. Which is why this time I'm eager to get my hands on the XPro-1, even if the AF has not been improved. Even if the write speed is the same as the X100. (I don't shoot continuous with any rangefinder, and with single shot, this is NOT a problem with the X100).
I guess these X series cameras are not for people who buy with their heads (thinking in terms of specs and value for money) but are more for people who buy with the heart, who are after a particular shooting experience which is different. (of course I do wish these cameras will be cheaper too!!!)