Here's the (pretty hefty) qualifier for the world's fastest AF claim: "Compared with other compact digital cameras equipped with an APS-C sensor and a non-interchangeable lens based on CIPA standards and conducted in High Performance mode." I guess this means it beats the Leica X2 and the Merrils, but what else is there in that category? I'd expect some improvement but I'm not holding my breath for any miracles. I'll never forget the early reaction to the X100, for which Fuji had made similarly grandiose marketing claims about the AF - first all sort of folk were claiming it was a revelation, then it was pretty good, then it was rationalized as "well, you remember the GF1 with the 20mm - its about like that", then the chorus gradually changed to IT SUCKS!. And it didn't actually change during that time, just the rationalization process slowly breaking down. I think I was probably in there with the "about like a GF1 with 20mm" group and, fortunately, its gotten better since then, particularly in low light. I always found it to be plenty acceptable, but never thought it was fast. Same with the X-Pro, at least with the 18mm lens I use most of the time - the 35'll frustrate me a hair every now and then. I like the looks of this camera, but I'm mostly happy about the sensor and the faux-rangefinder manual focussing. And I HOPE they add a quick menu and change the auto-ISO implementation to match the way they do it in the X-Pro, X-EI, X10, etc - that always bugged me.
But I'll wait and see before passing judgement. And I don't see getting one - I had an X100 that I loved but sold it after getting the X-Pro because I just wasn't using it. The only way would be if I decided to totally abandon the X-Pro system and I don't see that happening - I'll get a couple more lenses and may eventually but an upgraded body because the X-Pro 2 will probably have a lot of the same stuff in the X100S or may leapfrog it by a step or two in some areas. Or maybe not - I"m really very happy with the X-Pro as is, even without the world's fastest AF!
-Ray