Very interesting point in Galaxy S4 review
I came across this in a review in Wired.. (http://www.wired.com/reviews/2013/04/samsung-galaxy-s4/)
"But all that business of waving your hand or moving your eyes to scroll while reading — it only works in the crummy Android browser. It does not work in Chrome, where I do all of my browsing. It doesn’t work in Google Reader or Flipboard or Instapaper or the Kindle app, where so much reading happens. Looking away from the screen doesn’t pause a video in YouTube, only in the Samsung video player. The trick where you wave your hand to advance songs only works in the default music player, not in Rdio or Sonos, where I do most of my listening."
The so called "long list of features" of Galaxy S4 are just a bunch of apps.
I was under the impression that it was stuff that they added to android itself so that it would work across the board..