To be honest i'm not really an experience photographer when it comes to tracking moving subjects although i have the "theories" embedded somewhere in my brain. One theory is to use Not-so-fast shutter speed or otherwise the subject looked static, not moving at all.
Last weekend, i had the pre wedding photoshoot session with the motorcycle and just for fun, i'm gonna take a picture of them riding the motorcycle. It was 10pm, low light, the roads are all lit with ambered/orange colored road lights which gonna look suck in the photos and i just have to rely on my cameras to do the work for me. Pre-focus, and continuos high speed shooting. Its gonna be an experiment. For this work, i kinda trust my Olympus for its high speed AF although i did give my X100S a fair chance, the Fuji did nailed it but as it was in different lighting situation, the rider's faces were a bit too much shadow, i prefered my Oly pics for this..... if i dont pixel peep. Most of the Olympus pictures were in the right lighting condition or at the right moments. And even Oly did not accurately nailed focus everytime. and of course these pictures look great if you're not zooming pixel peep style. 4x3 or even 8x10 should be fine without showing not so sharp faces.
Here's one from EM10. i used the olympus 25mm.
i adjusted the white balance and thanks to the filter fitted in front of the lens, i get the blue flare. (clapped hands....NOT)
Here's from X100S.
Forget the colors. Forget the white balance. Pictures like these i'd prefer to convert it into black and white. as you can see the girl's face has too much shadow.
But the point is,
the x100s is able to get in focus with moving subjects.....in low light too.
But for the above 2 pictures, i'd prefer Oly for its moments and composition.