I think what he means is that the iPhone dots seem to move based on vehicle acceleration and deceleration, whereas the android ones use all phone motion.

If I move my iPhone around in my hands the dots don't move, but on my android they do (ie are simulating a stable horizon as the phone tilts, immediately). I don't know which is more effective. I thought the iPhone one was broken at first and didn't have the best results from it, I'm hoping the less-subtle android ones will work better for me.

Edit: I read from the docs that Apple's works best when facing forward, and I was often sitting sideways on a train

Yeah, probably could have phrased that better.

They are using completely different approaches. Apple seems to be mostly using the accelerometer, to draw dots and visualize inertia. The Android apps are using the gyroscope, to draw a horizon.