Of course, statements like that will be a lightening rod when made as an "in general" statement without any proof other than the user's impressions and theory. Mark clearly stated these were his impressions of the S2, then proceeded in the usual LL mode with an "as fact" demeanor. He also does say this ...
"At least in theory, it should surpass any other (AF) system currently available."
Personally, I do not question his impressions of the S2 AF system ... I do question which competitive MFD AF he is basing his impression of "better" upon, which isn't clear (unless I missed something).
Like Guy, I tried the S2 prior to current firmware tweaks, and had an almost identical experience ... using the release button was less than stellar even in bright, clear conditions, and improved considerably by assigning the AF to the rear thumb button. Even with the rear button, I could not get the continuous AF focus to work right and gave up trying ... but that may have changed. All-in-all, I expected a vast improvement over my then current H3D, and while better, it was not that much better ... in fact the difference seemed minuscule probably because my expectations were pretty high and I was hoping to replace my Pro level 35mm DSLRs with the S2 ... NOT my Hasselblad system.
My personal comparison point now would be against the H4D. I have no idea how a current S2 would do compared to a H4D without shooting both in similar conditions. What I can say is that the H4D is the best MFD AF I've used to date ... with the caveat that I've not experienced the current S2 with firmware updates, or Phase One's latest camera.
I know that Hasselblad has continuously improved the H system AF with firmware tweaks, and/or new models, culminating with the current H4 AF system.
I cannot overstate how well the "True Focus" with micro-adjust that's based on aperture selected ... and the new focus re-compose innovation ... actually works in the real world. The H4D's low light performance has also been improved with a simple increase of the AF assist intensity, and making it white rather than red. While not on par with a 1DsMKIII, it was just as fast than my assistant's 5D in real world, low-light situations.
In the case of focus/recompose situations, the H4D is actually faster than wheeling any 35mm DSLR's focus point where you need it, and then focusing. Plus you can place the H center sensor at the far edge of the frame then recompose, where that is not possible with a 35mm DSLR ... where the focus points are not that far to the sides, so you wheel the focus point, then shift the rest of the way and then focus and then recompose anyway.
Lastly, I am just like Guy when it comes to focusing in the studio for commercial assignments where there are three things to remember:. Manual. Manual, Manual. In most of these cases I prefer using the H waist Level finder with its flip magnifier for dead-on accuracy, and have a diagonal split micro-prism Bright Screen installed. The S2 and Phase cameras do not offer a WLF.
-Marc