A completely different situation than what WaterRockets presented. In fact, I would say that the motorbike example is not a difficult focusing situation at all; the bike is relatively small in the frame, and is moving horizontally - perpendicular to the shooter's line of sight. heck, one could take a cheap point & shoot, pre-focus on the middle of the track, and nail focus on every pass. Not an AF challenge at all. (And yes, I do realize that the rider is on a slight curve, but that really does not make a difference when you can just pre-focus on one part of a track and wait 'till the motorbike gets there).
The swimming image presented by WaterRockets is truly an AF challenge. The subject is big in the frame and moving towards the camera. Add to that the fact that the contrast between the subject and the object surrounding the subject (the water) is continually changing as the swimmers head bobs up and down, above the water's surface, then below the water's surface, interrupted by the transitional period when the emergence/submergence of the head causes splashing, which introduces yet a different, additional change in the degree of relative contrast.
The two scenarios are so completely different - one a huge AF challenge and one a very easy AF situation - that it surprises me that anyone would compare them to each other in an attempt to make a point about the AF abilities of any particular items of gear.
Agree. I have 5dmk3 and Fuji XT-1 and so far I am having hard time with Fuji for shooting action. But then the other day I saw someone had posted shots of her kid running at him with Fuji 56mm f1.2 and camera nailed most shots at f1.2. Even my 5dmk3 can't do that. How he did it, and if the keeper rate is repeatable, I am still trying to figure out. I will see if I can find the link.
Biggest problem for me being used to Canon is that on Fuji, their back button focus implementation is totally different. And VF lag when shooting action is very bad. Some of this will improve as time passes. Right now there are only 9 Phase Detect AF points in center. Sony A7r has no phase detect points only contrast detect so that is why AF is slower than Fuji. But the dynamic range is awesome and MF is so nice with focus peaking. I tried A6000 in store and AF is very very nice, almost as good as most dSLRs. This camera had so many phase detect points. If sony put same thing in A7r, A7r sales will go up. Sony needs to work on fast primes though. Fuji is doing very very good there.
For my portraits I use mainly 70-200mm f2.8 IS II and 5dmk3, sometimes 85L. If I replace all those with XT-1 and 56mm f1.2 and new Fuji 90mm f2 or the 50-140mm f2.8 OS, I will be happy for carrying less than 1/2 the weight of my dSLR kit.
I look at your galleries, awesome stuff but I can imagine you would be happy if you can do same with something that weights say 1/2 of your current gear even if it was more expensive.